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Full text of "Concrete and constructional engineering"

mm 



Umiv.qf 

To H UNTO 




\\ 



CONCI2ETE 



Volume IX. 



1914. 



Published at 4, Catherine Street, Aldwych, London, W.C. 
Editorial Offices at: 8, Waterloo Place, Pall Mall, London, S.W. 



INDEX. 



BOOKS, NKW : 

Architect's Standard Diary, The 

Cement Lime or Trass Mortars in the 
Construction of Dams. The Use of 

Chadwick Public Lectures on Housing, 
1913, The. By W. E. Riley, F.R.LB.A. 

Clerk cf Works. By G. Metson 

Concrete Pipes. By Riepert 

Concrete Products. By " Hollie " 

Elementary Building Construction, A 
1 Text Book of. Bv A. R. Page and Wm. 

E. Fretwell 
\ Experiments with Built-in Beams. By Dr. 
Fr. V. Emperger 

Fire Tests with Floors 

Handbook for Constructional Engineers 
in Reinforced Concrete. By Jean Braive 

Handbook of Structural Steelwork 

Handling of th*; Materials in Concrete and 
Reinforced (Concrete Construction, The. 
By Riepert 

Hydration of Portland Cement, Iron Port- 
land Cement, and Blast Furnace Slag, 
The. By Dr. F. Blumenthal 

Influence of Moi'^ture in the Air on the 
Volume of Cement Mortar, The. By Leo- 
pold Jesser 

Lockwood's Builders' and Contractors' Price 
Book for 1914 

Maintenance of Foreshores, The. By Ernest 
Latham, A.M.Tnst.C.E 

Making of High Roads, The. By Edward 
Carey, M.Inst.C E 

Manual for Ma-^on'^ and Bricklayers, A. By 
J. A. Van der Kloes 

Portland Cenient Manufacture. By Carl 
Naske ... 

Posts and Masts 

Practice of Construction in Concrete and 
Cement Mortar, Plain and Reinforced. 
(Translated into French by M. Darras) ... 

Reinforced Concrete Construction. Vol. II. 
By Gtorpe A. Hool 

Reinforced Concrete Construction. Theory 
and Practice. By A. V. Magnv 

Reinforced Concrete Railway Structures. 
By T. D Ball 

River Engineering and Drainage Work, 
The LTse of Concrete and Reinforced Con- 
crete in. By F Wichmann 



PAGE 

704 
427 

4-7 

70 

427 

286 

352 

212 
286 

426 
70 

427 

426 

426 

21 1 

211 

646 

210 

352 
212 

703 
210 

647 
69 



427 



Silo Construction in Concrete and Rein- 
forced Concrete 
Spon's .Architects' and Builders' Pocket 

Price Book 
Strength of I-Beams in Fle.xure, The. By 

Herbert F. Moo;-<» 

Technical Studies of Mortar and Cement. 

By Dr. Hans Kiihl 

Tests of Bond between Concrete and Steel. 

By Duff A. Abrams 

Training and Employment of Boys in the 

Building Trades of London 

Transactions and Notes of the Concrete 

Institute 



CEMENT : 

Hydration of Portland Cement, Iron Port- 
land Cement, and Blast Furnace Slag, 
The. (New Books) 

Influence of Moisture in the Air on the 
Volume of Cement Mortar, The 

Portland Cement Manufacture. By Carl 
Naske. (New Books) 

Some Fallacies in Cement Testing. By W. 
Laurence Gadd 



CORRESPONDENCE (See MEMORANDA). 

EDITORIAL NOTES : 

Concrete Cottages 

Concrete Cottage Competition, Our 

76, 147, 222, 364, 435, 437, 

Concrete Industry and the War, The 

Concrete Institute, The ... ... 217, 293 

Concrete fc>r Roads ... 

Concrete for War Purposes 

Concrete, The Uses of 

Considere, Mr. Arniand. (Obituary Notice) 

Cottages .. 

Fire Resistance in Factory Construction ... 

Important Reinforced Concrete Works dur- 
ing the Past Year 

International Association for Testing Mate- 
rials 76, 

Italy, General Concrete L^ses in 

Labour Troubles and Concrete ... 

Panama Canal, The ... 

Rebuilding ... 



704 
646 
287 



426 
426 
352 



123 




219 
204 
75 
145 
651 



Reinforced Concrete and International In 

\estigation ... ... ... ... ... ... 219 

Research Work and Concrete 76 

Standard Method of Mea^urtment for Rein- 
forced Concrete ... ... ... ... ... 146 

Tanner, Sir Henry ... ... ... ... ... 2:1 

Technical Profef-s-ions and the War, The ... 608 

Timber Question, The 651 



gi-:xi-;r.\l : 

.-Mignm-nt Charts for Con'^tructicnal 
Formul.-e By Ewart S. Andrew-, B.Sc. 
Eng. 32 

.Annual General Meeting, T!ie Concrete 
Institute ... ... ... ... ... ... 374 

Bell Telephone Manlacturing Co. at Ant- 
werp. BuildicK for the ... ... ... ... 406 

Bending Moment Problem, A. By Ewart S. 
.Andrews, B.Sc. i-ng. ... ... ... ... 404 

Calculations and Details for Steel-frame 
Buildings from the Draughtsman's Point 
of View Bj- Cyril W. Cocking 259 

Central Arno Hydro-Electric .Station, Cede- 
golo, Italy, Reinforced Concrete at the ... 182 

Concrete Cottage Competition, Our, 3, 437, 

518, 5S I, 620, C66 

Concrete Institute, The ... 123, 176, 193 

217. 259, 339.. 374, 410, 482, 553, 731 

Concrete in Small Domestic Buildings . . 15 

Concrete Masonry in the Panama Canal. By 
John Geo Leigh 149, 223 

Cross Hill Service Reservoir 503 

Decorative Possibilities of Concrete, The. 
By C. W. Boynton and J. H. Libberton ... 266 

Deformation and Deflection in Concrete 
Beams 662 

Economical Design of Reinforced Concrete 
T-Bc-ams, The. By J. E. Griffith ... ... 588 

Elasticity of Compound Bars, with special 
reference to Concrete Columns. Bv Her- 
bert G. Taylor, M.Sc '.. ... 722 

Electrolysis in Concrete 323 

Enquiries (See Mt^morwda). 

E.\tensions to the British Museum (Rein- 
forced Concrete in the new King 
Edward VII. Galleries) 7 

Grand Stand, Hurst Park Racecourse ... 169 

Harbour Improvements at Iloilo, Philippine 
Islands. .\ Reinforced Concrete Wharf 
with Grouted Foundations 114 

Heimbach System of Combined Wood and 
Reinforced Concrete Piles and of 
Lengthening V/ooden Piles, The 189 

H.M. New Stationery Office. By Albert 
Lakenian, M.S. A. .. 36.5 

Hvdro Electricity Works, Chester, Concrete 
and Reinforced Concrete at the 108 

Ice H<^«use at Pasco, Washington, Reinforced 
Concrete .S48 

Ilkeston Secondary Schools, Reinforced Con- 
crete at the f'"9 

International Association for Testing Mate- 
rials, The .■•• 543 

Institution of Civil Engineers and Rein- 
forced Conciete, The 102 

Lighthouse Construction, Reinforced Con- 
crete V. Ca«t Iron for. By C. Wescmann 325 

Municipal F-;nf.Mne<ring Works in San Fran- 
cisco, TT.S.A., Reinforced Concrete in. By 
E. R Matth'ws, A.M. Inst. C.E 95 

New County I La II, The Use of Concrete in 
the Substructure of the ... 653 

New Law Courts at Kingston, Jamaica, 
Reinffrced Concrete in the v 

New Offices for the Boar<l of Agriculture 
and Fi'-hcries, Reinforced Concrete in the 77 

Panama Pacific E.xhibition. Reducing the 
I'ire Hazard. By John Geo. Leigh... ... 383 

Para Brazil, Reinforced Concrete Building 
at - . .•" 332 

Patents Relating to Concrete, Recent British 

237, 4^'9, fii4 

Presidential Address, The Concrete In-iti 
tute 731 

Pressures on liarth P-taining Walls ... ... 739 

Prison Buildings, Reinforced Concrete in. 
By AUxrt Laketnan, M.S. A . ... F,7S 

Problems in th.- Theory of Construction. 
Bv i:wart S. Andrews, B.Sc. Eng W' 



Railvay Bridge for the Mestre-Merano 
Road over the Upjier Venetian Railway, 
and a Tramway Bridge, Mestre, Italy, 
Reinforced Concrete 

Reinforced Concrete 7\ Cast Iron for Light- 
house Construction. By C. Wesemann ... 

Reinforced Concrete Chimnev, .\. By John 
W. Rodger ' 

Road at Chester, Reinforced Concrete 

Roof Timbers, Westminster Hall 

Rural Housing 

Shearing or Diagonal Tension Reinforce- 
ment in Beams. By Charles F. Marsh, 
M.Inst. C.E. 

Shear in Reinforced Concrete Beams. By 
Rohintan N. Frarn Mirza 

Slab Formulas for Reinforced Concrete De- 
sign. By Ewart S Andrews, B.Sc. Eng. 

Slender Struts. By H. Kempton Dy^on 160, 

Steel Centering, Col'apsible 

Standard Method of Measurement for Rein- 
forced Concrete. Draft Report by the 
Concrete Institute .. 

Statues, Reinforced Concrete 

Testing of Reinforced Concrete Beams, The. 
Bv John A. Davenport ... 

Theatre des Champs Elysees, Paris. Rein- 
forced Concrete \\'ork. By Albert Lake- 
man 

Use of Concrete in Coal Mines, The 

Usher Hall of Music, Edinburgh, The 

Viaduct, Langwies, Switzerland, Reinforced 
Concrete 

Viaduct, Martin's Creek, U.S.A., Reinforced 
Concrete 

Wallace-Scott Tailoring Institute, Glasgow, 
The. By .Albert Lakeman, M.S. A 

What is the best Ratio of Steel to Concrete 
in Reinforced Concrete Beams and Slabs 
from the £ s. d. Point of View? By 
Rohintan N. Fram Mirza 

Zoological Gardens, Reinforced Concrete 
Panorama. By .Albert Lakeman 



457 

325 

48 
540 
463 
594 

307 

509 

396 
242 

741 

176 
678 

451 

631 

475 
295 



316 
711 



INDUSTRIAL NOTES : 

Concrete Piles 

Concrete Tools, etc. ... 
Machinery, Concrete 



MEMORANDA 






^ --•■>•, 



353 
754 
694 



^9\ 



Action of Sea Water on Concrete ... 213 

Administrative Offices for the Port of Para 431 
Annals of the Mexican Department of Public 

Works lofi 

Belgium, Harbour Work in 73 

Blocks for Dwellings, Concrete 705 

Blocks at Cfoodwick, Concrete .s'J9 

Boat Ways, Rockhaven Harbour, N.D., 

Reinforced Concrete 141 

Breakwater at Glenelg, South Australia, 

Concrete 5^8 

Bridge, Lingfield, Reinforced Concrete ... 705 
British Fire Prevention Committee, The 

496, 648, 705 

Building By-Laws and Reinforced Concrete 213 
Catalogues and Trade Notices ... 74, 144, 216, 

359i 434. 500, 571. 606, 650, 708, 760 

City and Guilds of London Institute ... 605 

Concrete Forms, Removal of 359 

Concrete Hardening Material 216 

Concrete Institute, The 7>. 74. 429. 758 

Conference of Mining ICngineers 497 

Contracts '44 

Correspondence 292,571,^149 

Detroit Building Code, Concrete Specifica- 
tions in , ••• 431 

Drxjr in a Racket Court, Reinforced Con- 
crete 5*39 

Dundee Crait' Pier 43' 

Dwelling House ;it Nnivvich. Concrete ... 359 

JClrctrolicrs, Concrete 291 

ICiicjui rics 292 

I'irralum Notices 74.292 

Fence- Posts for Dinas Way, II.ivc rfordwest, 

Rc-in forced Concrete • •• '4' 

Fence Posts, Concrete ;■■ ■■■ '"'^ 

Fire Preventive and Fire Service Work ... 49'' 



FirL--R<sisiiiij4 lluiuuu- 

Firt- Wamiiiv^ I or Kaiinir^ 

Fo(ill)ri<li^c at llitiliiii, U«iiiloi< id Comrttc 

l-'raimJ Com ritr l-jiniiK" Ht <l 

Cicnii.iii Ri-^MilatioiJ> itKanliiiK Rciiiinn til 
Ci)ti( n tf, S'Miic Ntw 

Gonlwitk, I'onirttf Ulocks at 

(irftnln'iisf Construction, Rcinlurnd Con- 
iTfti- in ... 

Hospital Arcliitt t tnrt- an<i C'on^trut tioii 

Inqnirii's 

Intirloi kiiiij Concrcti' liiiKk I'ipi", A Nfw ... 

Jnti-rnational .Association lor Ttstin^ Mate- 
rials 

International ("oiiunss ol IJuililinjj; an<l 
Public Works, Foiiitli 

International I'nuiut cring Conyress, 1915 ... 

Iron ami Stctl Instituti', The ... 

Kirkaiav. The Late \V. G. ... 

Li\i-rpool An'hi t'-'lnral Association ... 

Manchester linihling Trades' l-xhihition, The 

Mancluster School of Architects 

Matthews. Prof. K. R 

Modern Concrete Chutes 

Newcastle Civil ICngineers' Students' Asso- 
ciation 

New Concrete and Steel Building in the City 
Northern Polytechnic Institute 

Oil Tanks, Concrete for 

Paint Protection for Portland Cement Sur- 
faces 
Pontoon in Australia, Reinforced Concrete... 

Port Talbot Dock Works 

Posts for Vineyards, Reinforced Concrete ... 
Quay Walls at Nantes, France ... 
Racket C<nirt, Reinforced Concrete Door in a 
Reinforced Concrete Telegraph Poles versus 

\V(X)dcn Poles 
Rheumatism, Reinforced Concrete and 

Roads, Concrete 

Roof Construction on Concrete Building ... 

Rosyth Naval Ba'-e 

Royal Agricultural Sh')w at Shrewsbury, The 
Scottish National Portrait Gallery ... 
Self-supportipg Concrete Towers 
Shelter Sheds on an Australian Railway, 

Reinforced Concrete 
Sieving with Standard Cement Sieves 
Society of Ivngineers, The 
Specifications in Detroit Building Code, 

Concrete 
Special Fire Ser\ ice Force, The 
Steel Cutting Fdges for Concrete Caissons... 
Strength of Over-wet Concrete, Some Tests 

on 
Summer School of Town Planning, The 
Survey Monument. A Concrete ... 
Ten Concrete Road Essentials ... 
Trade Notices and Catalogues ... 74, 144. 

216, 359, 4i4, 500, 571, 606, 650, 708, 
Treatment of Granolithic Floors, The 
Trunk Sewer, Reinforced Concrete ... 
Use of Concrete on Railways, The 

Village, A Concrete 

Wash for Concrete, A 

W^at'?r Tank of 600,000 Gallons Capacity, 

Reinforced Concrete 
Westminster Technical Institute, The 
Wire Ropeway Supports in Concrete and 

Reinforced Concrete 



PAGE 

7' 
7.S« 
4.<' 



.'H8 

-y-' 
708 



49'' 
3.S'J 
4.U 
J.S'> 
388 
705 
430 
759 

7« 

70O 
648 
143 

706 

5<>9 
289 

571 
497 
569 

359 

2«9 

706 
144 

430 
566 
291 

73 

759 
215 
140 

431 
648 

73 

357 
496 
649 
433 

760 

705 
706 
605 
291 
706 

74 
648 

213 



NEW^ WORKS IN CONCRETE AT HOME AND 
ABROAD : 

Architectural Possibilities of Concrete, The 604 
Bridge in California, Reinforced Concrete... 350 
Bridge at Tipperty, .\uchenblae. Kincardine- 
shire, Reinforced Concrete ... ... ... 421 

Bridge at Wickham Market, Suffolk, A 
Reinforced Concrete ... ... ... ... 133 

Bridge, Yoshida, Japan, A Reinforced Con- 
crete ... ... ... ... ... ... ... 691 

Chimney and Sight-seeing Tower at Dres- 
den, .\ Concrete ... ... ... ... ... 425 

Coal and W^ater Reservoir for the Marseilles 
Gas Works ... ... ... ... ... ... 487 

Concrete Block Buildings at Norwich ... 285 

Concrete Block Construction ... 68. 136, 209, 

iSc, 2S5, .irS, 423, 486, 494 
Concrete Block Houses, Newburn-on-Tyne ... 68 
Concrete Blocks at Port Talbot 282 



Concrete Blocks in West Africa 
CcMicrele (41 the Farm 

Cooling Tov.rr, Reinforced Concrete 

Corn Crib, A Novel Concrete Block Circle 
Dam on the Mississipjii River, CfK»n Rapids 

Hydro I'lectric Plant, Concrete 

Des;imparad(.-s Station, Lima, Peru, Rcin- 

lorced Concrete at the New 

Detroit Buihling Code, Concrete Spe( ifi- 

eations in 
Dome for the South Manchester New Syna- 
gogue, Reinforced Concrete 

Dome of Melbourne Public Library, Placing 

of Concrete for 
Gasholder lank at Hamburg-Fuhlsbultel, 

Reinforced Concrete 
Harrisburg Reinforced Concrete Protective 

Wall, The 

Hotel E.vtension at Margate, Reinforced 

Concrete in ... 
Irrigation System at Calgary, Alberta, Con- 
crete Structures on the ... 

Lamp Posts, Reinforced Concrete 

Lodge and Enquiry Office, Concrete 

Marconi Wireless Stations, Concrete Blocks 

for 

Metropolitan Railway, Reinf<jrced Jfoncrete 

in the New O-fiees of the 

Mill Construction, Concrete 
Motor Garage, Whitby, A Reinforced Con- 
crete 

New Electric Power Station, Port Talbot, 

Concrete Blocks in the 

New Government Ship Lock in Black Rock 

Harbour, The 

Paper Warehouse, Reinforced Concrete 
Raft and Fire-Resisting Floors in the Fac- 
tory Extension for the Wolseley Tool and 
Motor Car Co., Reinforced Concrete 
Railway Station at Kuala Lumpur, Malay 

States 

Roof Construction at Liverpool Cathedral, 
Reinforced Concrete 

School Buildings, Concrete Block 

Sea Point Beach Improvement Scheme, Cape 

Tov;n 
South .Africa, Some Concrete Works in 
Steel Con^truTtion in the Palace of Fine 
Arts at the Panama-Pacific International 

Exposition 

Talbot's Inch. Kilkenny, Further Concrete 

W'ork at ... . . 

Water Restrvvjir, Talbot's Inch, Kilkenny, 

Concrete Block 

Water Tower near Burton-on- Trent, Rein- 
forced Concrete 



.•09 
418 
1,0 J 
4 -'3 

74S 



43« 
4-'-' 
2«3 
'35 
<'43 
559 

490 

00 
753 

4-3 

345 
418 

/ 

48^ 

04I 

089 
62 

604 

203 

494 

562 
562 

489 
136 
136 
132 



RECENT VIEWS ON CONCRETE AND RE- 
INFORCED CONCRETE: 

Aggregates for Concrete Roads. By Sanford 
E. Thompson, A N. Talbot, and W. M. 
Kenney 278 

Architect and Structural Engineering, The. 
By William E. Brown, A.R.I.B.A 482 

Contraction and ll.xpansion of Concrete 
Roads. By R. J. Wig, N. H. Tunnicliff, 
and W. A. Mclntyre 277 

Design of Steel and Reinforced Concrete 
Pillars, with Special Reference to 
Secondary and Accidental Stresses. By 
Oscar Faber ... 

Differential and Integral Calculi for Struc- 
tural Engineers, The. By W'. A. Green, 
M.A. 

Examination of Concrete Failures for their 
Determining Causes, By R. S. Greenman 

Factory Construction. By Percival M. 
Eraser. A.R.I.B A 

Fallacies in Cement Testing, Some. By W. 
Laurence Gadd 

Finishing and Curing Concrete Road Sur- 
faces 

Forms for Concrete Work. By Allan Gra- 
ham, A.R.I.B.A ' 

Mixing and Placing Materials for Concrete 

Roads 
S.and and Coars-; Material and Proportion- 
ing Concrete. Bv John A. Davenport and 
Prof. S. W^ Perrott 



410 

5- 
744 
193 
123 

639 
339 
685 

553 



Storage of Coal, The Bv Henry Adams, 

M.Inst.CE. ... .^80 

Testing Concrete Aggregates. By Cloyd 

M. Chapman ... ... ... ... ... 599 

Use of Concrete in the Design of Mine 

Shaft Linings, The. By \\m. A. Weldin. 412 
Weslevaa Methodist Hall. Westminster, 

The. By H. V. Lanchester, F.R.I.B.A. ... 58 

REINFORCED CON(^RKTE : 

Bridge in California, Re'nforced Con- 
crete ... ... ... ... ... ... ... 350 

Bridge at Tippertv, Auchenblae, Rein- 
forced Concrete ... ... ... ... ... 421 

Bridge at Wickham Market Place, Suffolk, 
A Reinforced Concrete ... ... ... ... 133 

Bridge, Vo^hida, Japan, A Reinforced Con- 
crete ... ... ... ... ... ... ... 691 

Building for The Bell Telephone Manufac- 
turing Co. at Antwerp, Belgium ... ... 406 

Building at Para, Brazil, Reinforced Con- 
crete .^ ... ... 33J 

Central Arno Hydro-Electric Station, 
Cedeerolo, Italy, Reinforced Concrete at 
the ^ 18-' 

Chimney, A Reinforced Concrete 48 

Coal and"^Vater Reservoir for the Mar- 
seilles Gas Works 487 

Cooling Tower, Reinforced Concrete 602 

Cross Hill Reservoir 503 

Desamparados Station, Lima, Peru, Rein- 
forced Concrete at the New 207 

Dome for the South Manchester New- 
Synagogue, Reinforced Concrete 422 

Economical Design of Reinforced Concrete 
T-Beams, The ... 588 

Elasticity of Compound Bars : with Special 
Reference to Reinforced Concrete Columns 722 

E.xtensions to the British Museum ... ... 7 

Gasholder Tank at Hamburg-Fuhls- 
brittel, Reinforced Concrete ... ... ... 135 

Grand Stand, Hurst Park Racecourse ... 169 

Harri«-burg Reinforced Concrete Protective 
Wall. The ... 643 

Heimbach System of Combined Wood and 
Reinforced Concrete Piles and of 
Lentrthcning Wooden Files, The 189 

H.M. New Stationery Office ... 365 

Hotel Extension at Margate, Reinforced 
Concrete in .. 559 

Hvdro-Electricity Works, Chester, Concrete 
and Reinforr-ed Concrete at the ... ... 108 

Ice Hou'e at Pasco, Washington, Rein- 
forced Concrete 548 

Ilkeston Secondary Schools, Reinforced 
Concrete at the . . ... ... ... ... 609 

Inititution of Civil Engineers and Rein- 
forced Concrete, The 102 



P.\GE 

Lamp Post^, Reinforced Concrete 66 

Motor Garage, Whitby, A Reinforced Con- 
crete ... ... ... ... ... ... ... 60 

Municipal Engineering Works in San 
I'rancisco, Reinforced Concrete in. By 
E R. Matthews. A. M.Inst.CE 95 

New Government Ship Lock in Black Rotk 
Harbour, U.S.A., The 641 

New Law Courts at Kingston, Jamaica, 
Reinforced Concrete in the 40 

New Offices for the Board of Agriculture 
and Fisheries, Reinforced Concrete in the 77 

New Offices of the Metropolitan Railway, 
Reinforced Concrete in the ... ... ... 345 

Panama-Pacific Exhibition, Reducing the 
Fire Hazard .. ... ... ... ... 383 

Panorama Zoolog'^al Gardens, Reinforced 
Concrete ... .. .. ... ... ... 21 

Paper Warehoiise, Reinforced Concrete ... 689 

Prison Buildings, Reinforced Concrete in 575 

Raft, Reinforced Concrete ... ... ... 62 

Railway and Tramway Bridge, Mestre- 
Mirano Road, Italy, Reinforced Concrete 457 

Reinforced Concrete v. Cast Iron ... ... 325 

Road at Chester, Reinforced Concrete ... 540 

Roof Construction at Liverpool Cathedral, 
Reinforced Concrete ... ... ... ... 203 

Shear in Reinforced Concrete Beams ... 509 

Slab Formulae fo^r Reinforced Concrete 
Design ... .. ... ... ... ... 396 

Standard Method of Measurement for 
Reinforced Concrete ... ... ... ... 176 

Statues, Reinforced Concrete 67S 

Testing of Reinforced Concrete Beams, 
The. By John A. Davenport 451 

Theatre des Champs Flysees, Paris ... ... 631 

Usher Hall of Music, Edinburgh, The ... 295. 

Viaduct, Langwies, Switzerland, Reinforced 
Concrete ... 250 

Viaduct, Martin's Creek, U.S.A., Rein- 
forcei Concrete ... ... ... ... ... 316 

Wallace Scott Tailoring Institute, Glas- 
gow, The ... 711 

Water Tower nr-ar Burton-on-Trent, Rein- 
forced Concrete i32' 

Wharf with Grouted Foundations A 
Reinforced Concrete : Harbour Improve- 
ments at Iloilo, Philippine Islands ... 114 

What is the Best Ratio of Steel to Con- 
crete in Reinforced Concrete Beams and 
Slabs from the £ s. d. Point of View? By 
Rohintan N. Fram Mirza 85 



TESTS : 

Overwet Concrete, Some Tests on Strength 
of 357 



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CONCRETE 

AND 

COMSTRUCTIONAL ENGmEEmNG 



J 



Volume IX. No. 1. London, Janiakv, 1914. 

EDITORIAL NOTES. 



CONCRETE COTTAGES. 

In accordani^e with thr announcenienl contained in our December number, 
our present issue contains the C>)nditions of our Competition for obtaining 
suitable designs for cheap concrete cottages. (See page 3.) 

These conditions have been most carefully framed with a view to 
obtaining the best possible results. 

It is not necessary here to enter again into details regarding the 
premiums offered, etc., as these points were raised in our editorial 
columns last month and are fully set out in the Conditions. 

Sufficient emphasis cannot be laid on the great national importance 
of this question of the better and healthier housing of our industrial and 
rural population, and every effort made in this direction should call for 
attention and consideration. That the Authorities and the public are fully 
alive to this all-important matter is evinced by the reports and articles 
contained in our daily Press and from the numerous letters we have 
received on the subject. We therefore hope that a large number of com- 
petitors will enter for this competition. 

In conclusion, we would draw attention to another article we are 
publishing, in which w^e have reprinted the recommendations contained in 
a Report recently issued by the Departmental Committee appointed to 
inquire and report as to Buildings for Small Holdings in England and 
Wales, and which should be useful to intending competitors. 

IMPORTANT REINFORCED CONCRETE WORKS DURING THE 

PAST YEAR. 

In the past year considerable progress has again been shown in the use of 
reinforced concrete for public buildings at home and in our colonies, and 
anyone who has perused our journal during the last twelve months will 
have realised on what important buildings this form of construction is 
now^ being used economically and with quite practical results. 

As pioneers in the advocacy of the use of reinforced concrete, we 
cannot but emphasise again the value of this material, particularly for 

B 2 1 



IMPORTANT WORKS DURING THE PAST YEAR. [ CQNCKETE] 

buildings that are simple and straightforward in plan and of considerable 
area. For such buildings the advantages are considerable, and we hold 
that all public departments and municipalities should follow the very 
excellent example of H.M. Office of \W)rks, in adopting reinforced 
concrete in the interests of the public purse. As far as the municipal 
authorities are concerned, certain progress has been made in obtaining 
longer loan periods for buildings in which reinforced concrete has been 
used, and although this progress is a step in the right direction, w^e should 
have liked it to have gone further, but we have no doubt the Local Govern- 
ment Board will gradually develop a more modern policy. 

We would only point again to our current pages to show the varied 
uses of reinforced concrete, our articles this month including such im- 
portant works as the Extensions to the British Museum, the Jamaica Law 
Courts, and the structures demanding such exceptional requirements as 
the Mappin Terraces at the Zoological Gardens. 




L<VL.N(JNL1JJ1NG -wj 



£125 CONCRETE COTTAGE COMPETITION. 











£125 CONCRETE 
COTTAGE COMPETITION, 



The obieci of this journal is to contribute to the solution of the great rural housing 
problem of the day, and thus the folloiving competition has been organised. — ED. 



Tm: Propriclors of Coxckete and Construct ioxal Engineer ing invite com- 
petitive designs for suitable detached or semi-detached labourers' cottages. 
The materials to be used shall be largely or mainly concrete in some form. 
It is to be assumed that the cottages would be erected in one of the Home 
Counties of England (at least 30 miles from Charing Cross, London), at a prime 
cost to the owners of £12^ per cottage. The Competition is open to all persons 
residing in the British Empire, and the following premiums are offered : — 

First Prize One Hundred Guineas. 

Second Prize Fijty Guineas. 

Third Prize Twenty-five Guineas. 

Fourth and FiftJi Prizes .... Ten Guijieas each. 
The Assessors appointed by the Proprietors are : — 
Mr. Max Clarke, F.R.LB.A. 
Professor Beresford Pite, F.R.LB.A. 
Mr. Edwin O. Sachs, F. R.S.Ed. 
The following are the conditions of the Competition : — 

CONDITIONS OF THE COMPETITION. 

I. — The object of this competition is to obtain a design suitable for a 
detached or semi-detached labourer's cottage that can be erected at a prime 
cost to the owner of ;^i25 when put up in a series of six in one of the Home 
Counties on a site at least thirty miles from Charing Cross, the owner buying 
his materials and employing labour without the intervention of a third party. 

2. — Concrete is to be the primary building material used in the construc- 
tion of these cottages, and solid concrete, reinforced concrete, concrete blocks 
or hollow blocks, concrete partition slabs, or any other suitable form of con- 
crete will be acceptable. Lintols, sills, hearths, sinks, etc., are to be taken in 
concrete or artificial stone. Slates or tiles, if used, shall preferably be cement 
slates or cement tiles. Thatch, wood shingles, etc., are not permissible for 
roofing. Freedom from the usual restrictions of current bye-laws, etc., will be 
granted with the view of securing up-to-date practice. 

3. — It is understood that the cottages will be erected on adjoining sites, 
each measuring 65 ft. frontage by 200 ft. deep, the front of the site being on 
the east side of a 50-ft. main road running north to south and having a frontage 

3 



£125 CONCRETE COTTAGE COMPETITION. [CQNCKET ES 

line set back 2j ft. from the bounclarv. Xu ftnciiiij or pailis or land drainage 
are to be included for in tlie £^12^. Ground taken out for foundations shall be 
spread at the back of the site. The subsoil is clay. 

4. — It is understood that there is no main (hainai^c or g;as supply, and that 
there is a local water-supply service, but the ;£..i25 shall iiot include for a water 
supply to the house connected to the public water service or for any plumbing- 
or sanitary work or cquijiment ; but tlie necessary equipment shall be show n in 
the drawings, including- a length of 40 ft. of 4-in. drain in the direction of a 
cesspool located at the back of the building, and the w.c, the sink, etc., shall be 
shown in connection witli the drain leading to the cesspool. 

5. — There will be no restriction as to the number or character of the 
rooms, excepting as follows : — 

(a) The principal living-room (or parlour) shall not have a less area 
than 150 ft. sup., and the principal bedroom shall have a superficial area 
of not less than 125 ft. sup. 

(h) The entrance (outer door) of the building to the kitchen or living- 
room sh.all ])e an indirect entrance, and not a direct entrance. 

(c) The accommodation shall be for two adults, two male and two 
female children. 

6. — There is no restriction as to whether the cottage should be a one-storey 
building or com.prise a ground floor and a first floor. 

7. — All plans shall preferably be drawn on not more than one sheet of white 
W^hatman or Cartridge paper, size 27 in. by 20 in., mounted on cardboard or on 
strainers, so as to be exactly 28 in. by 21 in. over all, but two sheets will be 
accepted. 

The drawings to I)e in black lines onl\- ; the plans, elexations, and sections 
to be to a scale of J in. to the foot, details J in. to the foot, and the site plan 
1-32 in. to the fool. All shading or the like to be done in hatching, sectional 
parts on plans and sections, where the material is of concrete, to be tinted in 
light Prussian blue, and no other tints or variation of ink or greys or the like 
are permissible. 

If more than one sheet is used, all ^-in. scale plans, at least one section, 
the front elevation, and the table referred to in Clause i i shall be together on 
one sheet. .\11 flrawings sh.all stanrl on the sheets with their base {paralleled 
to the 27-in. edge oi the sheet. 

One detail at least shall be gixcn, namcK , that of an I^xlernal \\ all. 
A line perspective is o[)iiona], but shall not o<"cu|)\' moi-e than S in. bx' 6 in. 
H')f the i^aper. 

H.--;\ll the writing on tlie drawings shall be in plain black ])l()ck letters, 
the capitals not less than J in. in si/c and tlu- small Icltc is in proportion. 

The " headings " ol the sheets lo be in (•a|)itals not less than ',' in. Iiii^h. 
Names shall not be used on an\' ol the rooms, but the loilowing abbri'N ia- 
tions shall be applied :-- 

K Main ent ranee. 

II Ilall, lobby, or anteroom (if any). 

K Kitchen. 

P I/uing-njoni or parJoui' (if any). 

KP Combined living-room and k'ilehen (if any). 

Sc .Seuller\ or wash-house (if an\'). 

4 



/^'fncSPSK^ i^-^ CONCRETE COTTAGE COMPETITION 



KNOlNKl-RlNti ^. 



\i Hcdiooiii. 

Bl lialiirooni (il' an}). 

L Larder or lootl-storc (if any). 

C C\ij)l)()ar{l or closet (if any). 

W W'.C. 

d Dresser (if any). 

c Copper (if an\ ). 

s Sink. 

b Rath (if any). 

m Manhole 

9.- — In every room there shall he plainly written its superficial area in feet 
in black ink. All numi'rals shall ])e in j)lain block numberin<^- not less than I in. 
in size. 

10 — The beds for the inmates shall be shown in dotted lines, 6 ft, by 
2 ft. 9 in. for each adult and 5 ft. 6 in. by 2 ft. 6 in. for each child. 

II. — On the sheet showing- the plans there shall be a list (table) of the rooms 
with their two principal dimensions, their superficial area, their heig"ht, and 
their cubic contents. The rooms shall be named in the same order as in 
Clause 8. 

12. — On tiie slicet on which the plans are drawn there shall be g^iven the 
cubic contents of the building- measured from the bottom of the footing's up to 
half the height of any sloping- roof, or to i ft. above any flat roof. In the case 
of rooms a portion of which is formed by a sloping- roof the dim^ensions shall be 
taken up to half way between the ceiling- of the room and the apex of the roof. 

13. — All usual structural fittings have to be provided for in the price 
of ;^i25, including- a kitchen range, fireplaces, mantels, but not the w.c, sink, 
copper, or bath. 

14. — Accompanymg; the sheet or sheets of drawing-s there shall be the 
following- descriptive specification, typewritten (with a margin of not less than 
ih in.) one side of the paper (foolscap size), and arranged as follows : — 
Page I : Description of the building and anj^ remarks of the competitor. 
Pages 2 and 3: Short specification, with an exact description of the concrete intended 
to be used, and a specification of its method of execution. 

Page 4: List of fittings, etc., and the net prime cost prices at which they have been 
taken. 

Page 5: An exact statement of how the competitor himself arrived at the cost, data, 
measurement from plans, etc. Such statement, however, to exclude anj'thing like a bill 
of quantities. This specification shall be strongly fastened together at the left-hand top 
corner. 

15. — Strict adherence to the conditions to be aimed at. The assessors will 
be strictly guided by the limits of cost. 

16. — Regarding architectural treatment, there shall be no unnecessary 
features or ornaments, preference being given to simplicity of treatment and 
avoidance of fads in joinery and glazing. 

17. — The whole ot the designs will be exhibited in London. Delivery to 
take place at the registered ofliices of Concrete Publications, Ltd., North British 
and Mercantile Building, \\'aterloo Place, Pall Mall, London, S.W. 

18. — The designs to which premiums are awarded shall become the pro- 
perty of the proprietors of Conxrete and Constructional Engineering. 

19. — The drawings shall be sent in between May ist, noon, and May i^th, 
noon (1914) latest. 

5 



in:; concrete cottage competition. 



iCQNCKETEi 



20. — The decision of the assessors shall be linal. 

21. — Should the proprietors of Concrete and CoNsiRit iion.m, Mnc.inkerinc. 
be able to arrange, as they anticipate, for the erection of one or more cottages, 
according to any of the premiated designs for which an inclusive prime cost 
estimate not exceeding £12^ can be obtained, they will endeavour to have the 
author or authors employed to superintend the erection at an inclusive fee of 
10 per cent, on the estimate for the hrst cottage, and 3 per cent, on any further 
ones, or some other form of remuneration which sliall be over and above any 
premium awarded by the assessors. 

22. — Competitors are not limited to one design, but each design shall be 
presented on a separate sheet or sheets, and shall rank as an entirely separate 
entry. 

23. — All drawings submitted, excepting those to which premiums have been 
awarded, will be returned to the competitors upon application at dates to be 
announced in the public Press. 

24. — Xo motto or device shall be added to any drawing or specification, but 
with every set of drawings and specification handed in there shall be presented 
in a plain foolscap envelope a bona fide statement that the design presented is 
wholly the personal work of the author, and this plain foolscap envelope (con- 
taining the full name and address inside) shall have no superscription or 
distinguishing mark of any kind whatsoever on the outside. All the designs 
and specifications will be numbered by the promoters in order of receipt. 

NOTES. 

The following literature may be of use io would-ljc competitors : — 
(a) — Earlier copies of Concrete and Constructional Engineering, which f^ive 
useful information and examples of concrete cottages and similar buildings, can be seen 
at the principal architectural libraries or are obtainable from the publisher at is. each 
(or post free is. 3d.), and they are as follows : — 

Concrete Houses for die United States. (Xovember igoy, page 353.) 

A Village Hall Constructed in Concrete. (Xovember 1907, page 402.) 

A Concrete Industrial Village. (December igoQ, page 513.) 

Reinforced Concrete for f^arm Buildings. (December igog, page 516.) 

Concrete Blocks for Building Purposes. (March 1910, page 212.) 

Cottages at Newbiggin Made of Concrete Blocks. (September igio, page 688.) 

Reinforced Concrete Bungalows. (October igio, page 769.) 

Cheap Cottages in Agricultural Districts. (December igio, page gog.) 

Concrete House at Glencoe, HI., U.S.A. (March igii, i^age 230.) 

Concrete Block House on Gidea Park Estate. (June igi2, page 471.) 

Reinforced Concrete Buildings at Rowntree's Cocoa Works. (July igi2, page 528.) 

(.'oncrete BlcKjk Houses on the Gidea Park Estate. (August igi2, page 633.) 

Concrete ]ilock Cottages at Talbot's Inrli, Kilkc'nn\\ (Odohcr igu, l-rontispiece, 

and page 785.) 
Concrete Agricultural Cottages in Norfolk. (October igi2, page 732.) 
Concrete JJlock Cottages, Kilkenny. (Novemhcr igi2, i)age 854.) 
Concrete Cottages, (April igi3, page 288.) 

Concrete Cottages in South Wales. (Septemhcr igi3, page 643.) 
(Joncrete lilocks and Tiles in Norfolk. (.\o\ cinbcr 1913, page 7S().) 
(b) — Woiild-bf! coiiijHt itors can ohlaiii, ii()<)n \\rilt«ii aj>|)Ii( alion, jxisi iVcc, .1 book 
entitled " C'cnicnt Uses" from the Associated i'orlland Cement Maiudactiiicrs (i()()()), 
Ltd., Portland llfjuse, Lloyd's .Avenue, E.C., which gives useful information as to 
modern concrete practice. 

(c)— .Some useful information as to (oltaj^es is contained in a Report iccenlh' issued 
and entitled " Rfrport of the Drparlmentrd ('ommitlee on liiiildings for Small Holdings 
in England and Wales " (Ol'licial Abstract reprinted from the Pai liamenlai \ Paper 
[Cd. 6708], IS. 6d., obtainable from Messrs. \\'\nian .ind Sons, l'"etter Lane, 
London, ICC). 

6 



K CONM PlIC"riONAi: 
i. E,N(ilNKK«IN(f — 1 



JiXriiNSIONS TO Tllh: HRiriSIl MUSEUM. 




r '"AI^HB ) J >»l»«'l«'«l1V'MI|ll»'l»l|lWftH^'IIIBWf*y'''"'1|W'\;WVMW1'IM»l|lltl|flil<l|>);tJ'<»M«w«llllWiy'» J 



' ji>t?rai; EXTENSIONS TO THE 
' ff.irMf..'^' BRITISH MUSEUM, 

LONDON. 

REINFORCED CONCRETE IN THE MEW 
KING EDWARD VII. GALLERIES. 

Some very interesting structiirjlii'ork hjs teen executed in connection ivith the extensions 
to ttie British Museum, ivhich affords another striking example of the adT)antages of 
reinforced concrete,— ED. 




INTRODUCTION. 

Ii is plcasino- and interesting to know that in a building of such high 
importance as the new Galleries at the British Museum, which are to be 
associated permanently with the memory of His late Majesty King Edward 




Fig. 1. View showing Ceilinj^, etc., to Ground Floor Galltrv. 
Extensions to the British Mlselm, King Edw.^rd VII. Galleries. 



Vn., reinforced concrete has been used to a very considerable extent in the 
internal construction. Due consideration was given to the sound and fire- 
resisting properties of the structure to be erected and the Expanded Metal 
systems of construction were adopted. 



EXTENSIONS TO THE BRITISH MUSEUM. 




The work comprises 
the King- Edward VII. 
Galleries facing* Mon- 
tague Place, and the re- 
constructed North Lib- 
rary forming a connect- 
ing block between the 
new and the old build- 
ings. The new wing 
forms an extension to the 
nijrth side of the Museum 
and is the first portion of 
an extensive scheme em- 
bracing the south, east, 
and west sides. 

The new building is 
approximately 320 ft. 
long^ by 50 ft. wide and 
80 ft. high from street 
level to the top of the 
parapet wall. The foun- 
dation stone was laid in 
June, 1907, and, as will 
be seen from Fig. 2, the 
work is now nearing' 
completion. This illus- 
tration also shows that 
the north front is treated 
in the Ionic order in 
Portland stone ; there 
are twenty Ionic columns 
which start 14 ft. above 
street le\'el. 

FLOORS. 

1" h e r e a r c f o u r 
s u s p e n d e d reinforced 
concrete iloors :- Sub- 
ground lloor at entrance 
level from Montague 
Place ; gi'ound n<);)r ; 
Mc//aninc lloor ; and top 
gallerx' llooi- w ilh rool 
oNcr. J'ig- 3 shows 
some of ihc slrucMiu'al 
sicclwork, and typical 
tcmporai'\ limhciing and 



, fCN-STWliCriONAl 



CV t.NdlNL-l RlNd — 



EXTENSIONS TO THE liRITISJJ MUSEUM. 



expanded steel rein!orerimMil in i)<)sili()n ready to receive tlie concrete lloorin^. 
At tlicir respective levels the llaors are supported by built-up steel 




Fig. 3. Sho\vin{4 Reinforcement and TemporaryTiuiberint; to Flooring 




Fii^. 4. \'ievv showin.ii Reinforced Conciete Floorin.^. 
Extensions to the BE<iTii-H Mlseum, King Edward \'II. Galleries. 



EXTENSIONS TO THE BRITISH MUSEUM. 



IC^^CBETEJ 



Stanchions, set at 16 ft. S in. centres k)ni;itu(linall\ , on wliich rest longitudinal 
R.S.J, mains carrying- R.S.j. secondaries at 4 ft. 2 in. centres. The centre 




f 



long-itudinal bay is 25 fl. 6 in. wide, the two side longiUidiiial l)ays varying in 
width as the main walls diminish in thickness towards the roof. Fig. 4 shows 



10 



KNdlNKl.RINfi — , 



EXTENSIONS TO THE HRfTlSH MUSEUM. 



soiiu' of the rciiilon'ccl loncrctf liooriiiiL; laid and willi its loj) Kit to rcc-fivc 
sand and (H-nu-nl hiHldiiij^- for tin- siirracc finislics. 

Vhc sti'i'l staiuliioiis aio iMicascd in () in. brickwork coated witli lime and 




hair plaster finished in lime putty; the R.S.J, mains and secondaries are 
encased in concrete, splayed down From the flooring- to the bottom flanges. 

The sofht of the flooring Is h in. below the top flanges of the secondaries, 



1 1 



EXTES'SIOSS TO THE BRITISH MUSEUM. 



[CONCRETE] 



and as the reinforcement is laid on top of the secondaries ii is thus embedded 

h in. from the underside of the concrete flooring-. 

All the floors are 4 in. thick and thev are reinforced throughout witli \o. 

8, 3-in. Diamond Mesh Expanded Steel. 

Due consideration was g-ivcn also to the question of the floor surface 

finish to be used. In the first place, wood block flooring was chosen as a finish 

for the g-round, top gallery and the north library floors, but it was discarded in 

favour of cork plates, 
fastened down by a 
special preparation of 
bitumen laid on sand 
and cement bed- 
ding, 2 to I, 2h in. 
thick. The sub-ground 
and the Mezzanine 
floors in the galleries 
and the floor to the 
students' room over the 
north library are 
finished with cork car- 
pet, ^ in. in thickness, 
laid on sand and cement 
bedding^. It was neces- 
sary to have the sand 
a n d cement bedding 
2:t in. thick, otherwise 
the finished floor levels 
allowed for wood block 
surface would not have 
been maintained. 

In order to obtain 
the best possible re- 
sistance to sound and 
fire, consistent with eco- 
nomical construction, 
the upper floors are 
j)ro\i(k'(l witli an air 
sj)ace between them and 
the ceiling^s below. 

CEILINGS. 

The ceilings to the sub-ground and the Mcz/anine floors are flat and 
plain, and are of Expanded .Metal Lathing^ and plaster, suspended beneath 
the R.S.J.'s in the florjring by means of flat mild steel bars s|)ace(l 12 in, apart, 
hung- on edg-e in mild sKel hangers carried by mild steel clips fixed to the bott(jm 
flang-es of the K..S.J.'s. 

In the ground fl'K)r gfalkry, which is intended for the e\hibitii)n ol glass 
rmcl ceramics, and in the north lil)rary I'ne ceilings are suspended in a simiK'ir 

12 




Pi;4 



II 111 ' i.illcrie-. 



Extensions to the Bkitish Miseum, Kino HmsAKD VII. Gai.i.ekies. 



y,t'ONMPmriONAl 
cvKNdlNhl.PlNd ^ 



HXTIiNSIONS TO TIIIi BRITISH MUSEUM. 




\\;i\, l)ut llu'\ an- ornaincnlcd with ni()cl< l)cam>, Minl>: panels, cornicL'S, etc., 
as "-liown in h'iij^. 5. 'I'lii' iiu-lal i^iounds ol the inock Ixains, clc, (-(aisist 
of tlat mild sU'fl bar (MMdlcs, hciU to llic lU'ccssai y siiapc ami li\;'d 3 in. a])arl 
to llu' K.S.j.'s in the lloorinj^', and straii^lit round nald sUcl lods, srl u in. 
ai)art aloni^; llu' c ladKs and wired to them, to act as stilleners lor the Expanded 
Metal Lathiiii^, whieh is wiied to the rods and around the shaj)ed eradles. 

The i-!x|)anded Metal ialhiiii^ and plaster eeilinm to the top g-allery is sus- 

|) nded by means of 
( li|)s, hanj4'ers, bars, 
ete., from the steel roof 
trusses abo\e. It is 
(•ur\ ed and ornamenie;!, 
and as prints ancl draw- 
in<^s .are to be exhibited 
in this g-allery, the ceil- 
ing- is desig"ned for and 
fitted with roof-lig^hts. 



MAIN STAIRCASE. 

The main stair- 
case with its land- 
ings is of reinlorced 
concrete f r a m e d i n 
rolled steel sections ; it 
is primarily the means 
of access to the gal- 
leries, and is the cen- 
tral feature of the 
g-eneral scheme, par- 
ticular!}' at the top, 
where the lift grille is 
enriched with the Royal 
Arms in cast iron g^ilded 
and lacquered. 

The treads and 
risers were constructed 
ill situ in concrete, 

in. 




FitJ. 8. Details of Construction of Mock Columns in Galleries. 
Extensions to the B.jitish Museum. King Edward VII. Galleries. 



reinforced with 



j 



Diamond Mesh Expanded Steel embedded about | in. from the soffit, which 
is flush and finished in Keene's cement. The balustrade also is formed in 
reinforced concrete, marble facings are fixed on the treads and risers and on 
the balustrade. The balustrade to the circular light well on the ground floor 
gallery, shown in the foreground in Fig. i, is also of reinforced concrete 
faced with marble. 

The four steel columns in the staircase and the six in the north library 



13 



EXTENSIONS TO THE BRITISH MUSEUM. ^ NCRETEJ 

are made of steel angles, riveted together with llat bar rings, filled in solid with 
and encased in reinforced concrete. 

MOCK COLUMNS. 

Figs. 7 and 8 show clearl\- how the mock c-olumns in the galleries were 
constructed; they are formed of small steel angles, riveted together with flat 
bar rings, with Expanded Metal Lathing wired to them and covered with sand 
and cement 3 to i , 3 in. thick. 

ROOF TRUSSES, ETC. 

The built-up steel trusses carrying the rooting and the suspended ceiling 
to the top gallery are encased in reinforced concrete. 

At the roof level on the Montague Place elevation there is a reinforced 
concrete parapet wall. 

Over the radiators in the north windows on the ground floor level, shelving 
was constructed in sand and cement 2-|^ to i, 2 in. thick, reinforced near each 
face and covered in marble f in. in thickness. 

GENERALLY. 

The concrete throughout was composed of 3-^ parts of crushed 
clinker, i| parts of fine clinker, and i part of Portland cement; the plaster 
throughout on expanded metal hithing was composed of three parts of lime 
and hair mortar to one part of Portland cement, finished in Keene's cement; 
the concrete is nowhere less than 2 in. thick and the plaster nowhere less than 
f in. thick. Clean fresh water only was used for mixing purposes. 

The galleries have been erected to the plans and specifications and under 
the supervision of the architect, Mr. John James Burnet, LL.D., A.R.S.A., 
F.R.I.B.A. 

The Expanded Steel reinforcement for concrete work and the Expanded 
Metal Lathing for plaster work used throughout was supplied by the Expanded 
Metal Company, Limited, o^ London and West Hartlepool. 

Messrs. W. E. Blake, Ltd., of London and Plymouth, are the general 
contractors for the undertaking, and they ha\e carried out the whole of the 
work described in this article except the cork flooring finishes and the lift 
grille. 



1 I- 



y, C-ON.STPUC-nONAll 
A F.Nr.IMKI.RlN d -^J 



COXCRETH IN SMALL DOMESTIC BUILDINGS 




CONCRETE IN SMALL 
DOMESTIC BUILDINGS. 

From a Report of the Departmental Com- 
mittee appointed to Inquire and Report as to 
Buildings for Small Holdings in England 
and Wales. 



■S/"^., 



In 'vienv of the competition nve are instituting, and regarding nvhich particulars ivill te 
found in another part of this issue, the extracts gi'ven telotu may be of interest and use to 
those entering for the competition. — ED, 



In recent numbers of this journal we have dweU on the question of cheap cot- 
tag-es, and we have pointed out that the possibilities of concrete for this purpose 
have not yet been quite realised. In the Report of the Departmental Committee 
for Small Holdings, which was issued recently, considerable space is 
devoted to the use of concrete for cheap cottages, and we gi\e l)el()w the parts 
of the Report relating to this all-important question : — • 

CONCRETE. 

Ti6. We li.ive made careful inquiry into the value of concrete for struc- 
tural purposes in connection with small holdings. \\'e have inspected examples 
of concrete construction in its various forms, including- solid and hollow blocks, 
monolith and reinforced concrete, and we have had before us a witness who has 
specialised in work of this nature. We Uaxg also endca\ouif;d to ascertain 
what economy, if any, was effected by using concrete instead of l)rick, and 
whether any special circumstances accounted for its use in particular instances. 
iVt the same time we ha\ e kept in view the question of the suitabilit}' of the 
material for the purposes of dwelling'-houses, and the relati\e degree of com- 
fort secured by its use. 

117. Concrete has not been used so extensi\'el}- in England :ind Wales as 
in some other countries; in fact, it may be said scarcely to ha\'e been used at 
all for the building- of small houses, except in the form of concrete blocks. 
Moreover, there are at present \ery few architects or builders w ho have devoted 
much attention to its employment for building cottag^es. 

Comparison of the cost of concrete construction with that {)f brick is some- 
what dillicult, owing- partly to the fact that concrete work is usually carried out 
under conditions differing from those applying- to the equipment of small hold- 
!ng;s. For exrimple, it is seldom adopted unless there is a grouj) or block of 
h(juses to be erected, whereas Ikjus'^s on small holdings are usualh" isolated, or 
at most built in pairs. It is possible, of course, to estimate what brick 
construed ion would cost under circumstances similar to those in which concrete 
is used, and this is done in most of the following- instances, which, with the 
exception of the last, are examples of some of the concrete houses that we 
ha\e inspected : 



COSCRETE IS SMALL DOMESTIC BCILDISGS. 



[CONCRETE] 



(i.) Coumy .... 
Number and construction 

of hcuses. 
Cubic contents . 
Cost 
(ii.) County 

Number and construction 

of bouses. 
Cubic contents 
Cost .... 

Remarks ... 

(iii.) County .... 
Number and construction 

of bouses. 
Cubic contents . 
Cost .... 

Remarks . 



Essex. 

20. Concrete blocks, tile roof. 

11,500 cubic feet. 

jCi62, or 3*4d. per cubic foot. 

Essex. 

Several semi-detached. Concrete blocks, Eternite slate 

roof. 
«;),6oo cubic feet. 
;^i55, or 3"Qd. per cubic foot. 
About id. per cubic foot cheaper than brick. Some have 

been built for i^d. per cubic foot. 
Northumberland. 
120 at present. Concrete blocks, Eternite slate roof. 

11,000 cubic feet. 

£\2~. or 2"Sd. per cubic foot. 

The aggregate for the concrete cost practically nothing. 
The cost per house includes a due allowance for 
depreciation and working expenses of the plant for 
mixing the concrete and making the blocks, but nothing 
for roads. Estimated saving, as compared with brick, 
£\S per house. 

Devon. 

46 and two shops. Concrete blocks, Eternite slate roof. 

10,900 cubic feet. 

^167, or 3'7d. per cubic foot. 

Eine granite chippings were close at hand. The saving, 
as compared with brick, was stated to be 6d. per yard 
super, for labour and mortar alone. Haulage i^ miles 
up bad roads. 

Glamorgan. 

5. Concrete /;; situ, reinforced concrete roof. 

7,630 cubic feet. 

;^ioo, or 3' id. per cubic foot. 

Slag from local steel works costs only is. 6d. per cubic 

yard on site. No sand was required. Estimated cost 

in brick, ;^i30. 

It will be seen that some saving' is claimed to have been effected by the use 
of concrete, but apart from the fact that its cheapness is partly explained by the 
presence of suitable materials in the vicinity, or by other exceptional circum- 
stances, it is clearly unsafe to conclude that the economy effected on a lar^e 
contract could equalls well be secured if only a few houses were to be erected. 
On the contrary, it is improbable that concrete can compete at present with 
brick, especially in a district where bricks are cheap, unless a fair number of 
houses are to be erected. 

1 18. There are numerous patents for reinforcing concrete, but in i;ent.*ral 
these patent methols are expensive, and there is the further drawback th.it 
the firms supjjlying patent reinf<jrcements do not them.selves carry out tlu- 
construction, so that res<irt must be had to ordinary builders and contractors 
for the actual building of a house. If a large and experienced firm from a dis- 
tance be employed on a small contract the expense may be prohibitive, while, 
if a local builder be employed, the absence of technical knowledge, and the 
difficulty of ensuring a proper specification and adequate supervision, make it 
almost impossible to achieve a satisfactory result. 
16 



(iv.) County .... 
Number and construction 

of houses. 
Cubic contents (average I . 
Cost .... 

Remarks .... 



(v.) County .... 
Number and construction 

of bouses. 
Cubic contents . 
Cost .... 

Remarks .... 






CONCRETE L\ SMALL DOMESTIC liUlLDISGS. 



I U). In the cast' of a lari;c hiiildinj^ sclicinc, liowcvcr, llurc is littli- doubt 
tliat in inaiu dislriits of I'liii^land and Wales a suhslantial sa\inj4 could be 
eficcti'd b\ llu' usr ol coik ri tc. II \\\v pi-cuuiarx' a(l\antaj4c to !)(• derived from 
its eniplox nieiit iu plaee <>l l)ri( k (le|)en(ls to any extent upon ibe con- 
centration of a laii^e amount ol work \\iliiin a small area, it is obvious ihal tlie 
fullest econonu t^ould only be secured, so far as tbe e(|uij)ment of small liold- 
ini^s is conc-erned, w iiere tlie circuiiistances permitted of a considerable number 
of holdiui^s beini^- provided toj^elher on a lar^e estate. This system of 
(lev eloimient is so much to be recommended on other j^rounds that the necessity 
of resorlini;- to it, if concrete construcMion is to be carried out as cheaply as 
possible, cannot in itself be rei^arded as an obstacle to the wider use of this 
material, assumin*;- tliat its constructional suitahilitv is established. 

Whatever opinion may be held as to the practicability of utilising^ concrete 
on any extensive scale in connection with the eqliipmcnt of small holding's, it 
cannot be doubted that there are likely to be g^reat develojjments in concrete 
construction, and, in spite of all the difficulties that exist at present in securing" 
a reliable result with single building's of concrete erected under ordinary rural 
conditions, we have seen enough examples to convince us that efforts should 
be made to develop the use of this material. \W' propose, therefore, to g;ive 
some details of the v arious modes of constructi<^)n to which concrete is adapted. 

METHODS OF CONCRETE CONSTRUCTION. 

1 20. Concrete m.i\- be used for building" in the following" ways : — 

(ij It n-.ay be moulded into blocks or slabs, and these used for building" 
in much the same way as blocks of stone ; we have seen many 
cottages that were built in this way. 

(ii.) It may be filled in between wood sheeting", thus forming a monolith 
structure built up in situ. A number of the Hollesley Bay cot- 
tages were built economicallv in this manner, as the cost of the 
sheeting" was distributed over several houses. 

(iii.) It may be poured in a more liquid state into wood or iron moulds 
erected complete to the form of the building. This method has 
been a.dopted by Mr. Edison for his "poured cottages.'' 

(iv.) It may be filled into moukis laid horizontally, each mould pro- 
ducing one side of the building; these moulded slabs, when set, 
are put together to form the cottage. This method was described 
to us by a witness, the main points of whose evidence arc given 
on p. 19. 

(v.) It can be used as reinforced concrete, in which case bars or rods of 
iron or steel are used to take u\) the tensile strain. Such rein- 
forcement can be used more or less w ith all the above methods. 

CONCRETE BLOCKS. 

12 1. This method of construction is the one which we have found to be 
most commonly adopted. It is the simplest, and the existence of various 
machines for turning out bk^cks on a large scale makes this system easier of 
adoption than methods whicli inv(3lve m.ore continuous supervision as the- work 
of construction proceeds; for this reason, perhaps, it is the method which 

c 2 17 



CONCRETE IN SMALL DOMESTIC BUILDINGS. ICQISCBETEJ 



gi\es the niost uneven results. We ins])eete(l a (-onsiderable number of houses 
built on this system, and nearh alwaxs found tliat wet had driven through the 
walls ; in some few instanees the bloelvs w ere so ]>or()US as to make the houses 
unfit for habitation. We also found that the majority of the houses inspected 
showed a tendency to develop \ertieal cracks, extending- the whole height of 
the walls, not only throug-h the joints, but across the blocks themseKes; these 
cracks increased the diflficultv of securing a dry interior. In fairness, however, 
to the builders of some of the concrete-block houses that we saw, and in defence 
of the method itself, it must be added that we inspected one example of a 
number of such houses which were entirely satisfactory, the houses being- 
pleasing in appearance, well-proportioned (a result not always easy to achieve in 
handling- a unit so larg-e as the ordinary concrete block), free from cracks, and 
thoroughly dry inside. 

122. In building- houses of concrete blocks, it is important that the lengths 
of the \\ alls and the sizes of the openings for door and window frames should 
be, so far as possible, exact multiples of the size of the blocks. The actual desig-n 
of the concrete block has not been thoug-ht out so well in this country as in the 
case of a patent block used in Sweden, which provides for almost continuous air 
space. Hitherto blocks have usually been moulded with an air space in the 
centre, the inner and outer portions being connected at the ends. If the con- 
crete is porous damp is likely to strike through these solid portions; for this 
reason, the method of laying- double slabs on edge so as tO' form a wall with a 
continuous ca\ity is beings adopted in some places, and this method, if the 
work is carried out properly, is calculated to ensure a dry wall, even with con- 
crete that is slig-htly porous. If, however, double slab walls are necessary in 
order t^) obtain a satisfactory result, there cannot be much economy, in ordinary 
circumstances.^ in such a wall as compared with brickwork. 

CONCRETE IN SITU. 

123. In the second metliod it is usual to leave openings into which door 
arid window frames are inserted subsequently. For simple work, such as the 
foundations of farm building-s, this method is the best and most economical, 
but for a wall that is to be carried up an}' considerable heiglit, as in the case 
of a twfj-storied house, the cost oi framing- and sheeting is hea\'\-. K\'en if 
se\eral hmises are to be erected (lose together, so that one set of sheeting- mav 
suhice for them all, the cost of re-erection is considerable; at Holleslev Bav 
it was estimated, in thie case of a one-storey cottag-e, that the cost of building- 
iipuii this ni('thod was about cciual to that of a (j-in. bi'ick wall with bricks at 
30s. j)er 1,000 delivered on the site. 

MOULDED CONCRETE. 

124. Ill i};c third method, the door and window frames may be placed in 
p(jsition in liie nujuld, and the; concrete is liien jioured round them. Mr. I^dison 
has in\-ented a system whereby an iron mould of the whole house is set up, and 

the hi.ildiiig made by iKJiiring llic li(|ii!(l coiicrclc in ;il the top of the mould, the 
house thus becoming- a c<)niplclc riioiiolilh. \\\ ihis inctliod all joints are 
avoided, and it is claimed thai a house (an be linished in a lortnight. Since, 
lun\'e\(r, the mould alone (■<)sls abont /.'i,joo, it is (|nile clear thai it could onl\ 
j8 



r J, c-oN.N ruurrioNA I 

L«i.KNCiINKKI^iN(. — 



CONCRHTE IN SMALL DOMHSTIC /WILDINGS. 



])v piofitahK cniplnx i(! il ;i l.n'i^c iiuinhcr <>l lioiiscs ol idcnlic.il pallcin were 1<> 
])v iTi'cti'd ill close proximilv. A !• iciicli linn lli.il l);is iii;i(l(' use ol s;)nK' siicli 
mould chiiins ihal •! s;i\iiii; ol Iroin jo to ^o per ccnl. ran be cllcclcd, hut \\c 
l.avc no ex idv-ncc lo show how far this claim can Ix- siihstant ialcd. 

HORIZONTAL MOULDS. 

125. In the lourlh method each side ol the huildinj^ is cast in a iKM'i/ontal 
mould, thus formini; a lai'i^c slab, which is I'aiscd into a vertical position when 
it has set. The mould is \cr\- simple and inexpensive to make, as it is only 
neo'ssarv to lav a le\cl staj^inj^-, lor which purj)ose the floor or rool boards can 
be used. The door and window franies are laid on this staj^'inj^' and the mould 
completed. Its horizontal position fa<Mlilates the arrang^ement of the reinforc- 
ing- rods, and it is not nccessarx to make an upper side to the mould, as the 
concrete can be evenly spread and screeded off to the required thickness. A 
house al Letcdiworth was erected U|)on this system some years ag'o b\ the city 
cn5.^"ineer of Li\erpv)()l, clinker from llie refuse destructor being used for the 
aggregate. The method of construction was described to us by a witness, who 
has adopted it for the erec^tion of one or two buildings, and reference may be 
made to the Abstrav i of M\ idence (page 74) for detailed particulars. 

126. ^^ ilh all the (liferent methods of construction, in addition to any 
saving; effected in the actual cost of the concrete wall, as compared wnh one of 
brickwork, there is usually a considerable reduction in the cost of plastering, 
as a slight skimming coat is all that is required; indeed, it is possible in many 
cases to smooth-trowel the surface of the concrete as it sets, so that colour-wash 
may be applied direct without any plastering. 

CONCRETE FLAT ROOFS. 

127. The witness already referred to has also succeeded in making concrete 
flat roofs perfectly waterproof. It is true that the work is of comparatively 
recent date, but it has been completed long enough for defects to show them- 
selves if any were likely to appear. There can be no doubt that if further 
experience confirms the evidence that a flat roof of concrete 3 in. thick, without 
anv covering, can be made thoroughly watertight, such a roof would be con- 
siderably cheaper than any form of slate or tile roof. It was stated by the 
witness that a saving of ^£^15 per house could be effected, and we have been 
given figures sliowing an actual saving of ;£. 1 1 on the roof of a cottage with 
dimensions 27 ft. by 16 ft. 9 in. as compared with the cost of an ordinarv- hip 
or pitch roof of flat tiles. 

Some further experience is needed to determine whether there w(;uld not 
be a liability to excessive e^ondensation with solid walls and roofs not more than 
3 in. or -I in. in thickness. 

MATERIALS AND HANDLING. 

128. Whatever be the form of concrete construction adopted, or the nature 
of the work, the success of the result will depend on the use of suitable 
materials and their careful mixing. Waterproof concrete can only be made 
by using a thoroughly impervious agg-reg-ate, and so grading- it that the inter- 
stices between the larger fragments may be entirely filled with smaller par- 
ticles and clean sand; the function of the cement is then simply to bind the 

19 



CONCRETE IN SMALL DOMESTIC BUILDINGS. [CDNCBEJE] 

whole together. While bricks and other porous materials may make excellent 
concrete for fireproof purposes, or for ordinary foundations, they are not 
suitable for external walls or roofs, where waterproof properties are essential. 
For such purposes an aggreg-ate of j^ranite or g-ravel is best ; clean slag- or 
clinker may also be used if it can be relied upon to contain no impurities 
such as free sulphur or jDartially burnt material. 

W'c are convinced that the need for building- concrete walls hollow is due 
to the faulty work that so often results from the use either of an unsuitable 
agg-reg-ate, or, what is equally disastrous, defective cement ; and that if the 
fullest economv is to be obtained bv the use of concrete, it will only be by 
the adoption of careful and intelligent methods by wliich this necessity may 
be avoided. 

129. The Engineering Standards Committee has fixed a standard specifi- 
cation for cement, and none which fails to comply witli the British standard 
specification for Portland cement should ever be used where it is desired that 
the concrete shall be waterproof. This cement is usually supplied in three 
grades — viz., quick, medium, and slow-setting. Detailed instructions on the 
most scientific method of using cement of the quality known as British 
Standard, and of mixing concrete for various purposes, are issued by the 
Royal Institute of British Architects and bv the Concrete Institute. 



20 



I^r CTONyiPUCTIONAlJl 
L<V KNCil N l-W 1 N( ■ — J 



REINFORCED CONCRETE PANORAMA 




REINFORCED CONCRETE 

PANORAMA, ZOOLOGICAL 

GARDENS. 



By ALBERT LAKEMAN. 

This -work is'quite unique, and as an example of reinforced concrete con sir action there 
is nothing in existence -which in any -way resembles the problem -which has herein been 
dealt -with, and m consequence it has much interest to those -who study the lanous 
applications of this material. ED. 

'Jhe scheme described in this article is the outcome of a bequest by 
Mr. Mappin, who provided a sum. of money to defray all the expenses 
nection with the work. 

Tile primary object of the panorama is to show the animals m 



the late 
in con- 

such a 




Fig. 1. View showing Columns under Construction. 
Rkinfokckd Concrkte Panorama, Z( ological Gardens. 

manner that they appear in a state as nearly as possible resembling" the natural, 

and avoid the caged appearance \\hich is generally associated with animals 

kept in captivity. The architects for the scheme are Messrs. Belcher and 

Toass and it will be seen in Fig-. 2 that the plan is that of a quadrant, and this 

21 



ALBERT LAKE}] AN. 



ICQNCBETE 



has a radius to tlie exlrcnie outside of about 288 ft., thus the whoU' scheme 
covers an area of about 260,000 sq. ft. 

The panorama is divided up l)y tliree icrraces for ^i^it<)rs, and these are at 
varying- levels witii a wide flight of steps at either end for the passag^e from 
one le\el to the other. The centre of the quadrant \\ ill be occupied by a tea- 




■ ■ "'V-:-; 



\-' 



Fifi. 2. General Flan. 

Kl IMORCKD CoNCRKlK PANOKAMA, Z()i )I 0(.I( \r (lARDhNS. 

house, adjacent to which is the lower terrace, and imincdiatcly on the other 
side ()\ the len-acc a large (hi(l<-pon(l is being formed. I>e1ween llu- (hu-l^-pond 
.and the middle terrace there are four large ciiclosuies b)|- deer. A li-inforced 
concrete wall se]3arat<'s the latK r from ihe tcirace, and on the othci- side of tlie 
terrace iheie is a large drv diteii which is formed to ])r('\ent the Ix-ais Irom 
jumping- out of tlx: enclosui'cs whi(li o<(ur b(lw(en tlie middh- and upper 
terraces. 'i here are six lai'ge bca)' enclosures, and each ol these lonlains a 
water tanlc in which the animals can dis|))rl ihemsehes, while ihe suilace of 



22 




Rl^:i\'F()RCliD CONCRETE PANORAMA. 



till- ciiclosllic 



iindu- 



o 



hitin^ :in(l constructed 
l<) rcsc*ml)lc ii.it iir;il lix'ky 
•ground ;is lar as 
j)()sm1)1c. riic u|)])<'r Icr- 
1 a((' s('])aratfs tlic hear 
enclosures Ironi the ijoat 
liills, wliich are cjuile one 
<jf the most slril<in«4 lea- 
lures of ll.c scheme, 
these risin;^ up to a 
height of about 70 ft. 
from the ground le\ el 
and being grouped to 
form four distinct liills. 

These hills are 
shown in outlin'j in i1k' 
section in Fi^\ 3, \\hi(^li 
indicates somewhat the 
uneven nature of the sur- 
face and shows the ditli- 
5 N cultv of the bracing for 
s such an irregular con- 
^ ^ tour. The photograph 
^ cC in Fig. 4 gives a general 
.^ H idea of this bracing 
under construction, while 
u one of the finished hills 
g can be seen in the dis- 
I tance, although the full 
s height is somewhat lost, 
as the view is taken from 
the middle terrace and 
not from the ground 
level. 

The section in Fig. 3 
also shows the dens for 
the bears, which are con- 
structed under the upper 
terrace. The i^ear en- 
closures are separated 
from eacli other by high 
division walls, which are 
formed with concrete 
iKning a surface which 
is just as it leaves the 
centering, and a rustic 

23 



I § 



O ES 

o 



t- ~ 



ALBERT LAKEMAS'. 



ICDNCBET FJ 



effect is obtained bv the use of wire nettinii'. wiiicli lias allowed the concrete to 
bulge. At the same lime j^reat caie and thouiilit has been devoted to the work 
in order to avoid any projections whicli would enable the bears to climb up the 
walls and escape. Tiu' slal)s in ihc bear i-ndo-^urc are illustrated in Fig. 5, 
and it will ]yv seen that thi- thickness \aries from 5 to 7 in. 

Xo beams in the ordinary sense of the word could be formed owing- to the 
irregular surface of the slab, but these were formed in the same thickness by the 
introduction of additional bars for a width of alx)ut 2 ft. 6 in., and these beams 
followed the same lines as the slabs. The reinforcement in the latter consisted 
generally of |-in. bars at lo-in. centres in one direction, ^-in. ])ars at about 




P/iotuKrap/i hy J:nicst AHlnei .\ 

l-'vA. t, Hraciii^i to Second (ioat Hill. 

Kl.IMORCII) CoNCKfcTK I'ANOKAMA, /(OLOGICAL GakOI.NS. 



I Luiulcn, S.W 



3 {-in. cenlrL-s in ihc o])p;jsilc dircclioii. Some of the Ijars arc luriicd up and 
passed o\'er the ixams, as shown, and slirru|)-^ arc also ))ro\i(if(l. 'llu cnlumr.s 
were also made of diffcent heights, and the cciUcring for ilic slabs \\;is formed 
parti}' with planking and j)ailly with wire uctling, the lallcr i)c'ing allowed lo 
sag and tlius assisting in llic bninalion •)! ihc un(hilal ions. 

'ihc, water tank's in lhc-.c cix losiircs lorm inlci'csling examples of rein- 
forced concrete, as th(;\' are j^( neralK' susjx-nded from 1 he ( ohnnns .md sl.ibbing, 
■.\])(\ arc lormed with a \ crv irregulai' sli.ipe, ;is will be seen in the 
pliot<;graj)l)ic \\c\\ in /'/^^ 7, uliicli shows ilie andei'sidc of one lank. 
Despite the I ict thai wo j)ai'li(ula!' j)rec.iul ions were taken with the 



24 



f, CONXIVUCrKaSAll 
A KNGINKI-PINC. ^ 



REINFORCED CONCRETE PANORAMA 



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-3 



ALBERT LA K EM AX. 



[^^CCETEJ 




26 



' J, CTONM PIJC riONAl.l 



REINFORCED CONCRETE PANORAMA 



work, these tallies Ii;i\i' hccii Inimd lo he pcrrcctly u atcrlig'ht , aii<l 
il will he iindi islood thai ihcrc was sonic diHicuIty in lanij)in^ ihc concrete 
w lu-n poi lions of \hv su|)])()rlini4- cenierin*^- were C()m|)()sed ol wire neltinj;- only, 
riu- lari^cs! lank is thai formed in ihe exlrenie eastern enclosure, which will he 
occui)icd h\ till' |)olar hears, and this has a niaxinunn haij^th of ahout 40 ft. and 
a width of ahout 17 ft., with a (le|)lh of water of O ft. This tank is fitted at 
the deep end with four observation windows 2 ft. by i ft. <) in., throug-h which 
the bears can be seen when under water and their moxcnienls noted. 

The dens, which are formed under the upper terrace, are each about 12 ft. 




Photograpli by Ernest Milnerl [London. S.W 

Fi^. 7. Under side of Bear Pond, showing Suspension. 

Reinforced Concrete Panorama, Zoological Gardens. 

by 6 ft. and 6 ft. 6 in. high, and these ha\e floors, walls, and ro'uf of reinforced 
concrete 5 in. and 6 in. in thickness, with reinforcement in both directions and 
surfaces. The wall adjacent to the enclosure is continued up above the floor of 
the upper terrace for a height of nearly 7 ft., to prevent visitors being seen 
from the lower terrace levels, as this would detract from the natural appearance 
as far as the animals are concerned ; but small windows are being formed in 
the wall to allow a view into the enclosures from the upper terrace. 

The construction of the goat hills required a great deal of careful considera- 
tion and setting out, as they arc very irregular, and yet of necessity they need 
to be rigid, on account of the height. Two typical sections are illustrated in 



ALBERT LAKEMAN. 



ICONCBETEJ 





li;i. 'J. View showing Middle 1 cirace iit-ai JMicluMircs, etc. 
REINFORCBO CoNfUl II I'ANOKAMA, ZoOI.OGlCAL GaKDKNS. 



28 



REIN FORCED CONCRETE PANORAMA. 

.- c , , n . , .Irn llnoiwh llic Mvcnd and ihird hilN. Tin- lower part 

"■'• ^' ^'^'^^" ^""' s n^.ral rows of columns, about .7 it. h^^h above 

..I tlif construilion ronsisls 01 stxtiai n>\Nr> •, , • 1 1 • 

,£:"i:::';.:;l>::::i:':.':n.:;::r:::;;,r f':i £ 
;l-;::::;-^i;^;''c;:;r-;:::;n:::.:j::::.'J;.-";t 




»-?63 



I I |i ij im millllllll V I lllliMmilj J ummma 



__po-'»J 



Fit5. 10. General Plan, showing Arrangement of Columns. 
Rkinforced Concrete Panorama, Zoological Gardens. 

scuu-c bavins a mininuini Uiicknoss at the otlicr edges of 9 i"-. increased to 
,8 in 'at the intersection with the column shaft. The tops of the colutinns are 
connected bv radial and tangential beatiis which vary in s,ze from 9 '". by in 
to 14 in. bv' 9 in. according- to the position. .All the columns and braces above 
these bcanis are 9 in. by y in. and reinforced with four ?,-m. bars and hnks 

29 



ALBERT LAKEMAX 



[(jQNCBET D 



Spaced :il 12-in. centres. 'I'he si)ace under the second hill is partially occupied 
bv a lari^e water tank, shown in F/^^ 8 on the Diagram A, and this tank 
supplies tlie ponds in the bear cm^losures. It has a mean width of 30 ft., a 
length of 2- ^^-^ ^"d is 3 ft. 9 in. deep. The hoiiom and sides are formed with 
5-in. reinforced slabs carried by 14 in. l)y 9 in. main beams, and 9 m. by h m. 
secondar\ beams, reinforced g^enerall\ with four ^-in. bp.rs and iV-in. slirrujDS. 
The water from the goat hills is collected and taken to this tank, and the over- 
flow is connected to the main supplying the bear ponds, and the latter can be 
quickly filled, as the tank is constantly full and a supply always available. 

The trussing- under the third goat hill, marked B in Fig. 8, is somewhat 
different ow ing- to the intermediate columns being omitted with the object of pro- 




1 ■,.. 1 i-' •ir J.inJ'jMiiL- (lui in;; Coni.u iiuin-u. 

Rl.INl OKf KI) C0N( KKTK PANOKAMA, XooLOdlCAL GaKDKNS. 



xiding" a large iiall th.il (.in be utilised lor m;iii\- ])ur|)oses, such as lectures on 
natural history. I uo rows ol coluiniis oiil\ .lu- cmploNcd here, ;iiid large rein- 
forced <f>n'rcte Irusscs h;i\ing a s[):in ol .iboul 4J ll. are consl ru( led ;is shown 
in the seeiioii. 1 he llii<kiiess ol the covering sl.ibs \;iiies soin.'w h.il accoiding 
t(j the j)osili(jn and kjading, but ihe minimum ihickness emjiloyed is 3 ins. These 
slabs were forj7";ed by ramming the com reie between two l;i\'ers ol wire nelling- 
spaced .'il ihe distance apart i'ec(uired lor ihiikness, :in(l ilie rainniing of ihe 
concrete caused the netting to bulge and produce ;m iiregul.ii- surl.ice, and in 
addition iIh- line slull j)roj;(ted through the linles in the nelting. 'ihe outer 
surface v\.is tre;it(d with .i still I)roi)ni, which c.iused iliis projecting stuff to 
spread and cfj\er the iHlling eniirel_\, .md ;i! the s;inic lime ;i suil.ible surface 

30 



[/:LNr;iNK'p[K?Sg REINFORCED CONCRETE PANORAMA. 

finisli \\;i.s ohl.iiiu'd. I he oiilcr surlacc is 1 IicrclOrc siiHi(iciill\ roii^li lor iIil* 
*;"();its to cliinl), ;im(I is iciiilorci d i)\ lin- nctliiii^, wliicli is (juitc .idditional lo the 
main rriiilorccnunt ol llu- slab itscll. Ilic wliolc apixaranct' is wrv pleasing, 
and wlu 11 seasoned and loncd down hy ihc wiatlu-r slionld i)rescnt a very natural 
effecl. A ladder is |)r<)\ ided in llie interioi- of the hill to allow the keeper lo 
pass u|) to tlu' lop with lood, which is passed through a feeding hole at this 
{X)inl, thus indueini; the ^^oals to elinil) well u|3 into the \ie\v of the visitors. 
A safety railin*^- is fixed on the outside of the hill some wav down from tlu toj) 
to prexent unfortunate i^oats from being- butted or fallin*^- to the ground belou . 
The staircases leading- from the lower to the upper terraces are 14 ft. wide, and 
they are reinforced with bars in the sofHts in both directions, and an intermediate 
transverse l)eam is also j:)ro\i(led in the centre of each flight. The landings are 
formed with 5-in. slabs also reinforced in the sofhts in l)()th directions, and the 
bars in the flights are carried well into the landing concrete. 

The whole of the concrete is being mixed by machinery, and the j)ro- 
portions generally adopted are 1:2:4. 

The Consulting Engineer for the scheme is Mr. Alexander Drew, of 64, 
Victoria Street, and the contractors are Messrs. D. G. Somerville & Co., Ltd., 
of 120, Victoria Street, Westminster. 

It will be readih' understood that the nature of the work necessitated a 
great deal of ingenuity in the execution, and many points had to be left to the 
foreman on the site, especially with regar 1 to the irregular surfaces of the bear 
enclosures and goat hills. It was quite impossible to indicate the complete 
contour of all these irregular surfaces on the drawings, and scale models were 
therefore made for the guidance of the contractors, who are executing the work 
in an excellent manner. It would not have been feasible to construct this 
panorama in any material other than reinforced concrete, and for this reason the 
w^ork probably illustrates its adaptability to any form of construction more 
clearly than any other example in the country. 



31 



EWART S. ANDREWS. 



[QONCBETE] 




ALIGNMENT CHARTS FOR 

CONSTRUCTIONAL 

FORMULiE. 



By EWART S. ANDREWS, B.Sc.Eng., M.C.I. 

The foUoivlng article should call for the attention and consideration of Engineers ana 
others interestea in this subject of Alignment Charts.— ED, 



Within recent years an intereslinj^- method of plotting charts, known as the 
Aliirnment Chart method, has been extended very successfully to use for 
engineerini,'- formuke. As far as the writer is aw^are, the first use of these 
diagrams in a British publication is to be found in the Structural Steel Section 
Book recently issued by Messrs. Redpath, Brown and Co., Ltd. The method 
is, I believe, of French origin, and has been developed very largely by Pro- 
fessor Peddle, of the Rose Polytechnic Institute, U.S.A., in articles in the 
American Machinist and in a book entitled "The Construction of Graphical 
Cliarts " (Hill Publishing Co.), in whi(^h this and other interesting methods of 
graphical representation are set out. 

In the present article it is pro])osed to explain the nature of the.se charts 
and to .show how they can be drawn, illustrating the method by constructing 
cliarts for suitable well-known constructional formulai-. 

Underlying principle of alignment charts. 

'Jhe constructi(jn is based upon an unusual method of pk)tting (^o-ordinates. 
The m.ethods commonly considered in co-ordinate gi^ometry are the Cartesian 

or rectangular co-ordinate method 
:in(l the polar co-<:)rdinate method. 

The rectangular method is 
shown in Fi^. i, which represents a 
lin-ear function n.x \ hy~c. 

1 1 w ill he rcMicmbcrcd that in 
this inclhod ')! plotting x'alues a and 
y arc liikcii in directions at right 
angles to each other and (^or- 
res|)on(liiig to simiill ;ineous \alues 
of X and \ \\v gel a |)( )inl /'. 

In llie method Innning llu' basis 
ol llie alignment elKirl two |)arallel 
lines, .V V, ) 1' (/''.i;'. 2), are <lra\\'n at 
a conxcnient distance d apart, and 




Fig. 1. 



3^- 



J. CONyiPlKTIONAn 
tV t.NOlNKll^lNd — ^J 



ALIGNMENT CHARTS. 



.stiirlin;^ lioni llic l);isc liiir V ) we set ii|) A /' ((lual lo v ;iii(l lO, ((jiKil to y. In- 
>U'.i(l<)l li;i\ ins^ ;i point lo ri'|>rcstiit ^iiniilt;invous \ allies ol a ;iii(l y uc now li.ive 
llu' str;ii|L;hl lin<' /'fj,- Xou si'.pposiiii^ th;it .v .ind v .'H'l- ioniu'ctcd toj^ctlicr l)\ ;i 
liiUMi' relation ol the loiiii (/ah l)y c (i), and supposing that new \ aiucs ol 
V and y arc found and j)lotlcd lo j^ixv |X)ints 1*^, O.^, tlicn l*.JJ._. euts l\(Jt in S, 
and if cciuation \^\) holds, .S' will \h- a iixcd point called the support, so thai 1)\ 
])Utlini4 one straij^iil edi^c thioui^h an\ particular \alue ol a, and also ihrou^h .S , 
the cdi^i' will intersect the line ) ) at the ]H)int which will enable us to lead oti 
at once llu- correspondiuLi' \alue ol y. I^( lore pr<jceedinj4 to the j)rool of this 
lad it must be pointed out tliat an alteration of .S' upon the line AS, called the 
" support line," will i^orr-jspond lo an alteration of the constant c in the fc^rmula, 
and b\ obtaininj^' a suitable scale for lenj^''ths upon the line AS we can treat c 
as a variable quantity, and so use the (diari for soKinij- an ecjuation in which 
there are three variables. 

Proof of construction : — 

Oraw .S7^ and FT horizontal. 

Then the A^-^ SOJ^ and PST are similar. 
ST _ PT 

' ' Q.R~ SR 

z—x XA e 



I.e. 



y-z AY f 
We will assume that S 




is a fixed point — i.e., s = constant, and 

constant. 



Y ^ 



Fig. J 

For convenience we will wTite this as 

x^ — 

a a 

D 2 



AY 

z — X _ e 

y~z f 
or /(:r-A-)^c(y-3), 
i. c. , fx -r ey -^ ez ^- jz^ 
i. e. , fx -r ey -- z{e + /). (2) 
\ow z, e and f are con- 
stant, so that equation (2) 
represents' a linear relation. 
It is shown, therefore, 
^ that by drawini^' from \alucs of 
A- on the line A'A' through the 
support, the resulting' value of 
y on the line VY follows the 
linear relation of equation (2). 

Going' bacd<, therefore, to 
the original equation (1) we 
have 

ax -i- bv = c. 



(3) 



33 



EWART S. ANDREWS. 



and \\ c will write (2) as 

= ^(^-l)(4) 



, ey z{e-\-f) 



/ 



(5) 



From (3) and (4) we gel 
e ^± ^ 2^t 

and 

c _z (a^b) 



•SO 



i.c 



or z 



a 



a 



a + b 
It will be noted that 

.'■ re-writing (5) as 
e _ b 



[-(6) 



-r 



--50 



e+/ C7 + 6 

we see that 
a Tb^ 



(7) 



rs- 






(8) 



272 



ICQNCKETEl 

t5 



- ?'5 



•4-0 



-■/5 



^1 

I*' 

A? -I 



'10 



o 



Fifi. 3. Chart for French"Reinforckd Concketf. 
Formula. 



A\ e n<jle also that the values of e and / are independent of the constant c, 
whereas z depends on c, so that, as pieviously stated, by alterin^^ the constant 
we do not alter the support line, but only vary the position of the support ujDon 
the line. 

Scai.es. ^ — Suppose that for the sake of convenience in certain problems the 
X and y Icn^^ths ar(- plotted to different scales, say, i in. =.S'^. units for x and 
I in. = .S^ units for y. 

Then we shall ha\e 



e = 



bS. 



aSx -f- bSy 
and the scah- for the sup[)ort \alues will be 

S, = ] inch=aS,-\-bSy 
Example of Reinforced Concrete Column Formula. 



(10) 



It is now pr<;i)(jsed to illustrate the use of these diaj^n-ams or alignment 
charts by drawing'- one for the formula for h<'lically r<inforce(l concrt le columns 
specified by the French (iovernment, viz. : — 



V V ' 



(11) 



34 



r J, CONM PlJC-nONAi; 
L*VF:NrilMLF.WlN(. — . 



ALIGNMENT CffARTS. 



In this lormula 

Q = l*criiiissi\ c coinprc^six t slnss jht >(\. in. on llic {(jlunin. 

1^ =l'lliin;iU' coinijicssix (• stress on tin- <<)n(Ti'te. 

\'^ — \\)lunu' of core. 

)',, = X'olunie ol lulicMl reinforeenicnl. 

\'^=\'olume of lonyiliuliniil reinforeeiiunt. 
I lie reinforcements are usually sj)()k<n of as ])ercenta|^es. 

. <. 1 •. r 1 • r . 100 \^, 

Let j^/, = o longitudinal reintorcement — 

^ _,. V r 1 ■ ( ,_100V^/ 

M pn— -> helical reintorcement— - 

I'herefore, re-writinj^ our lormula, u e lia\e 

— =•28(1 -ISPL+'iiPn) 
u 

= -28+ '0^2pL+ •090pH (12) 

Starting- at a convenient point set out pj , the per cent, longitudinal rein- 
forcement, to a suitable scale, say, i in. - '5 — vS^, taking a range of values from 
o to 3 per cent. Then set out at a convenient distan(^e d = ^ in. away from this 
line a scale of helical reinforcements —the same scale i in. = '5 = 5y will be 
suitable. 

In our formula a — "042, b =- 090. 
Therefore by equation (9) 

_ • 090 X • 5 ^ c _ o . - 9 • u 

e = - X 5 — 2 /2 inches. 

•042X -S+'OgOx -5 

The scale for -^ is given by equation (10) 
u 

S,= -042X -S-h-OgOX •5=-066 = l inch. 

The constant '28 shows us that when p^ and pn ^^^ each equal to O, 

— ='28, so we know that the line joining the points 0,0 intersects the sup[X)rt 
u 

line at '28. 

Since i in. - '066, '02 will be given by ^- --^o^ in., so settino- up --.o:; in. 

•066 ^ 1 . ^ 

from the bottom we get the "30 mark for ^ , and so gel the other divisions as 

indicated. The divisions are not continued bexond Oo because the regulations 
state that the compressive strength shall not exceed '6 of the ultimate strength. 
Suppose, for instance, that we have a column with i per cent, longitudinal 
reinforcement and 2 per cent, helical reinforcement, we place a straight edge 
across the corresponding ix)ints on the chart, as shown in dotted lines, reading 

If, therefore, n = 2,000 lb. per sq. in., c will be about 1,000 lb. per sq. in. 

Extension to Product Formulae. 

The alignment chart may be applied to product formulae (which arc much 
more common in practice than those which we have considered up to the pre- 
sent) by taking logarithms, thus bringing the formula into linear form. 

35 



EWART S. ANDREWS, 



[CDNCKETEJ 



Take, for instance, P" 0"" = /?''x A, where .4 is a constant. 
Taking log^s. we get : — 

)i log-. P -- 111 log. O -= p \og. R + log-. A. (13) 

\n aliL^nmcnt chart can then be drawn for this formula in the manner 
pre\ iously explained, although gr-.-ater care is required for the plotting. 

Example of Formula for Steel Beams. 

This case can be illustrated In' th-e well-known formula for steel beams 



where -Unsafe bending moment on the beam in inch tons, 

/=safe stress m tons per ^q. in., 

Z-- section modulus of beam in inch units. 

For a uniformly 

distributed load upon 

a span of L feet, 

WxiUL) 
M = ^ ' and 

/ is usually taken 
as 7-5. 

Our formula, 
therefore, comes to 
12WL 



8 



7-5Z 



or 



TFL^SZ. 



V\li. 4. (MART lOK StI I I. liKAMS. 



(H) 




(15) 
log. IF + log. 

L = \og.s + ^og. Z. 

We \vill take a 
range of W from 
10 — 150 tons. 

log. JV varies 
from I to 2' 176. '^ 

A suitable s(\ale ^o 
for this will be "^ 

1 in. = Sx = 5, and-^ 

Fig. 4 w as originally q 

drawn to this scale. ^ 

With a lit lie jjractice ^ 

these logarithmic 

scahs can be drawn 

w i 1 h comj)arati\ (■ 

ease. Take, lor 

instance, a coii- 

\ enient point near the 

bottom of the right-hand line of h'ig. -] and mark it 10. Xow log. 150 -log. 

iO-hlog. I5 = l()g. 10, \\J<>, so lake a distant'' i(|ual to 5X|-|7() 5'SS ni. 

above the 10 line and mark it 150. 'i"o lind inu rmcdiatc; pn'wWs \\v j^-ocei d in 

exacth the saiiu manner. i'or ^(j, tor instance, we ha\c 1< 



;o 



OiJ 



10 



36 



J, OONMVUCn lONAl, 



ALIGNMENT CHARTS. 



-_l()_i;. u) I "477. "177 '<> <>i"' ^'iilc is ■-477x.S = -WJ i'i. iu';irl\ , so mark .1 
point J\><) in. ;il>o\c ilu- 10 111. iik ;iii(l (.ill il ^o ; tlic s.iin; disl.ii.cc ;il)o\c this 
j)oiiil will i;i\ i" t)o. 

On tlic opptisiic side ;il ;i conx cnicnl (lisLiiuH' :ip;irl s:i\', 5 in.- uc draw 
IJK' /. line ;in(l we will lake as a suilahh- ranj^c ol \ahu's ol /. 5; 11. lo 30 II. 
Ia)^. 30 loi^-. 5: lot;. 10 I. riic same scale, 1 in.=.S"y= l, will he ron- 
\cn'\vu\ lor this, so mark a cominicnt point 5 and set up 5 in. .ihoxc it and 
mark that point 50, ohlaininj^ inti-rmrdiate pinnts in the manner jjrcN ioush' 
deserihed. 

'JO draw the Z scale we Inst lind ihc j:)osition of the supj)ort line as 
follow s : — 

By i^"C|u:ition (9) c^ ^_5>l ^ ^. 

a Sx~\~b Sy 
In the present ease a = b ^- i , d^z^, Sx = Sy = h 

5 ' 5 
We therefore draw in the Z line as shown. \e\t its scale is determined 

by equation (10), viz. : — 

Sg = (i Sx-^b Sy 



Xo record has been kept of the zero points of the (T and L .scales, and we 
do not require to know them, because it is ^een by putting TT^i^io and L=^^ 
in equation (15) that Z=io. We therefore join across the points 11':= 10 ;ind 
L = 5 as shown in dotted lines and mark the intersection on the Z hne to. 

The Z scale is then divided up as follows: — Take, for instance, Z^200, 

log. 200= log-. 10 + log. 20^ log-. 10+ r^oi ; to our scale this is given by 

1 * 301 X 5 

in. =3'^5 in., so set up V-5 inches above the 10 ]>oint and mark it 

200. The chart is then soon completed. 

To use it, suppose that we want to hnd the section modulus necessarv for 
a beam to carr\ a uniformly distributed load of 40 tons o\er a span of 30 ft. ; 
place a straiglit ed^e across the points 40 and 30 as sliown in full lines and 
read of Z = 240. From a table of standard sections a suitable section can 1x' 
found at once, or if beams of a definite t} pe onl\' are used the sizes can i)e 
marked on the Z line at the opposite side. 

In actual use of the chart it is not necessary to draw the lines aci'oss ; it 
is better not to do so. 

Extension to Four Variables. 

These charts can be extended for use with four \ariables in the following 
manner. We will illustrate the point by a consideration of the same formula 
for steel beams, but will take the stress as variable. Our formula is :- - 

^^^=yz (16) 

i.e., log. Z=^log. r5 f log. rr + log. L - log. /. (18) 

Let i; = log. ir + log. L. (19) 

37 



EWART S. ANDREWS. 



The loij-. 1-5 m:iy be neglected for the present because it has only the 
eftect of shift ino- the zero for the Z scale. So we may write 

log. Z = log. V - log. /. (20) 




20- 



l''i(4. 5. Chart i ok Sikki Hi ams uitm Xakiaiu.I'. Sikess. 

Fig. 5 has been dr.iwn lo rcprcscin this fonmila, and bcfort; describing the 
manner in which il is dr;,u.i it uoiiid be ucll to indic.ite the maimer in which 
3« 



fy,cr>N>ipm-nc;NAu ALIGNMENT CHARTS. 

i- tNCilNhl-.lJlNd :--^ 



il is used. Sii|)|)<)sf ih.il we li.ixc ;i l<);i(I ol 70 tons on a span of 30 ft., tlie 
working stress Ixiiij^ (> tons per s(|. in. IMa(<- a straij^ht vi\^v alonj;^ the* |x>inls 
70 and 30 on tlu' IT and /. scales resi)e(li\ c*ly (as sliow 11 in dotted lines) and 
mark the intersection of the 7' or common sU|)|>ort line; join this intersection to 
the i)oint / (»; liien its intersi-ct ion on the Z scale f,^i\es the modulus required, 
viz., 525. 

To draw the s<\iles we first decide upi)n the ranj^'c of ahies and take 
1 1 ' Irom 10 to 1 50 tons. 
L Irom 5 to 50 i I. 
f from 5 to 10 tons |)er scj. in. 
Takinj^ d' and /. lines at 5 in. a|)art and plottin*^ each to a scale 
1 in. =S/ = Sw "- "- i'l-. iJi^' loj^arithms of the \alues are plotted conveniently 
by the method pre\ iously explained. 

Since in this case a — b—i and .S\. =5^=2, we have 

^ = 5X ''L =2-5 in. 
•2+*2 

Support scale i in. = 5^ — "2 + '2 = '4. 

We do not need, however, to plot values on the support, because it is not 
used for reading from, but we use this result later to obtain the Z scale. Now 
draw our / line at, say, 4 in. from the common support and choose a suitable 
scale, say, i \n. - S^ — 'i. 

It will be noted in equation (20) that log-. / has to be subtracted, so we 

set values of log. f downwards, as shown, instead of upwards. 

1 X * 1 
The Z support distance from tlie v line will tiien be e^^ 4 = 5 = *8" 

• 1 + '4 
The Z scale is i in. =r 5 , — i x ' 1 + 1 x '4 = '5. 

We have kept no record of our zero points, so that to get a p)oint on the 
Z scale we take convenient \alues in the original equation (19) — TF^ioo, 
L= 10, /= 10. 

^ 1-5X100X10 , -^ 

*; — "^ 

We therefore join across as shown in full lines and mark the mtet section 
on the Z line 150, obtaining otlier points on this scale as previously described. 

To e-et Z=^o, for instance, we have -^ =3. therefore log. i ^0 = '477 + log. 

50 
50. Xow "477, to a scale i in. = -5, is "954 in., so mark this distance down from 
the point Z— 150 and mark it 50. 

The endeavour of the above article has been to show how to draw and 
use these alignment charts rather than to gi\ e a large number of charts of use 
to engineers. Most of the formulae used by designers can be charted in this 
manner, and such charts are very useful for designing. 



39 



NEW LAW COURTH AT KINGSTON, JAMAICA. 



ICOSCBETB 







REINFORCED CONCRETE 

IN THE 

NEW LAW COURTS AT 
KINGSTON, JAMAICA. 



A former ar'icle dealing ivith these ttr'ldinas ivas published in our Journal, Vol. VI, 
p. 85, and the fol'oiung particulars, ^ith illustrations and drazu-ngs showing details of the 
reinforced concrete construction, may therefore be of particular interest.— ED. 



OuK readers will no doubt recollect ihat we have already published, in one of 
our previous numbers, a short description of this new building, which was then 




West Front in course of construction. 
Nkw Law Coi'ins at Kinjisk^n, Jamaica. 



in course ol consl ruriion, and wliicli has now been recently (■()nij)lcted. 1 lu; 
enlire slriicture is in rcinloncd ( oncrclc on liie C'oij^nct System. 

'J'his l)iiil(iing is llic third public luiildini^ crecMed on this s\stcm :it Kingston, 
the architects apj)ointc(l b\ t he ( jo\ ( iiiiin nl Ix ini; Messrs. Nicholson <V C'orlctle, 

40 



A LN(UNLU/1N(, ^J 



NHW LAW COURTS AT KINGSTON, JAMAICA. 




41 



NEW LAW COURTS AT KINGSTOX, JAMAICA. 



ICQNCPFTFJ 




\ I 



r f 



C j 

^ f 
-- t / 



^U 



^:t 



i 






y 



I 



3 



-f^- 



V 



Hir. 



^4j 







77^ 






.^ 



. av«.»| V 



His-.; -■•i; , I 




o < 
o s 



o c 

O z 

a; "^ 

o < 

OS D 

«t-i o 

O U 

I ^ 

lu 1-4 



r »^ oav.Trut jcnoKAq 



NHW LAW COURTS AT KINGSTON, JAMAICA 



ol I^nulon. I lie otiu'i- l)iiil(linj;s were the new Klnj^'s House, or Residence of 
tlir (loNcrnor, ;in(l llu' l*(>sl Ollice ;incl Treasury building's. 

All this i^rou]) ol huildinj^s, which has been desij^ned b}' the architects for 
the special j)ur|)()se of olferinj^" the greatest pcjssible amount of resistance to 
earthcjuake shocks and lire, has been designed on the same architectural lines. 

y.Ach building is constructed ujion a strong; reinforced concrete raft distri- 
buting the load uniformly upon tlie ground, and the entire building is braced 
together in such a manner that it constitutes a thoroughly monolithic structure, 
and it has been proved by actual experience that this method of construction is 
the iK^st suited to resist earthquakes. 




Interior View, Kingston Court. 
New Law Colrts at Kingston, Jamaica, 

As shown in the accompanying photographs, this building is surrounded by 
spacious verandahs in order to prevent, as much as possible, the rays of the 
sun penetrating into the rooms. All the roofs are flat and are protected from 
the heat by a layer of gravel several inches in thickness. As shown in the 
photographs illustrating the interiors of the court-rooms, the ceilings are kept 
as high as possible to ensure proper ventilation. In fact, every detail of the 
design has been carefully considered to suit the tropical conditions of the 
climate. The wooden fittings, such as benches, platforms, and doors, are made 
of solid mahogany. 

The general dimensions of the building are as follows :— A total length 

43 



MEW LAW COURTS AT KISGSTON, JAMAICA. 



ICQNCBETEJ 




44 



fy , rONSTkt Il-nONA 1 , 



NEW LAW COURTS AT KINGSTON, JAMAICA. 






- I 



U. I 



45 



NEW LAW COURTS AT KINGSTON, JAMAICA 



ICQNCBETEJ 



of about 258 ft. and a total width of 92 ft. in the smallest width and 136 ft. 
in the larg-esr width, the heit^ht from the foundations to the roof being approxi- 
mately 45 ft. 

The building- is composed of a ground lloor, first and second floors, and 
a Hat roof. The stairs are also constructed entirely in reinforced concrete. 
The total area of each floor measures approximately 22,000 sq. ft. 

The plans for the execution of the reinforced concrete were prepared b\ 




Section of Principal Reinforced Concrete Floor. 




Cross Section of Reinforced Concrete Floor. 
Nkw Law Coi kjs at Kin(.ston, Jamaica. 



Messrs. I^dmond Cc^ignet, Ltd., of jo, \ ictoria Street, London, S.W., and the 
contract for th(t cxccuti'^n of the work \\;is (\'irri<'d out by Messrs. Mais & Sant, 
contracMois, of Kingston. The work w.is, of course, entirely executed by 
native k'llKHir und( r skilled siipcrx isioii, and this is another ))rov)f ol the 
adaptabililN' of reinforced (■on<r<t<: to colonial buildings. 

The reinforced cone rete sNstem which was used for this building is com- 
posed of a sp('cial arrangctment of ordinary round bars of mild steel, the columns 

46 



, CONMyUfllONAI 



ti-ENdlNKKWlM, ^ 



NHW L^WV COURTS AT I<INGSTOy,JAMAICA 



iH'iiii^' loriiH'd l)\ lour or iiiDrc iij)rii4lil l);irs siirrMiindrd l)\- spir;il lioDijin*^- of 
siiKill (li;iin('U r. 'I he he. mis ;ii'c cninpDscd ol one or more slr.iii^lit h.irs at llic 
1<)|) and hollom, (-omuclid IolicIIkt 1)\ xcrlical stirrups ol small diameter. 
'1 lu'S'i- sit el hames heiiii; prepared in adxanee on tlie site, llie\ are simply 
|)laeed in the moulds readx for (^oneret inj^'. 

1 he llooi- slabs, usualh about -] in. in ihiekness, are composed of a mesh- 
work ol bars spaced about 4 in. or 5 in. apart. The walls are made in a similar 
mamua' and ri'inloi'ced 1)\ means ol hoii/ontal and x'erlieal bars lormin"' a 
mesiiwork. 

Some t\j)ieal sections are i^i\cn in this article showing" ihe reinforcement 
ol columns, beams and floors, which clearK show the arrangement of the bars. 




Interior View Supreme Court. 
New Law Courts at Kingston, Jamaica. 



47 



JOHS W. RODGER. 



[CQNCBET El 






,i^^^T 



■■>^^:&:;. 



'V ^i-m^ 












<->'-4-.-:^'-' ^: '^m'i^^ 



m 










A REINFORCED 

CONCRETE 

CHIMNEY. 









By JOHN W. RODGER. 

The question of the suitability of reinforced concrete for chimney construction has been 
the subject of considerable debate ana also much doubt. Any information, therefore, 
relating to such structures ivHl be ivdcomed, as it 'will add to our store of knowledge on the 
subject. We, therefore, give below the following particulars of a chimney recently erected 
in South Wales.— ED. 



The South Wales Portland Cement and Lime Co., Ltd., are erecting a new- 
rotary plant at their cement works, Penarth, near Cardiff, and have built a 
chimney of a somewhat interesting description for carrying away gases from 
the kiln. 

The chimney is fourteen-sided externally and 220 ft. high above ground, 
formed in two parts, the outer of concrete blocks and the inner part or lining 
of bricks. The outer concrete shell and the inner brick lining are entirely 
unconnected throughout their full height. 

All steel concrete \v(jrk above ground was carried out by Messrs. Monoshaft, 
Ltd., under their patented methods. 

The blocks are composed of concrete in the proportions of 9 cubic ft. of 
crushed granite to pass a f in. sieve, with all fine and dust removed, 5 cubic ft. 
of clean coarse sand, and 3 cubic ft. of Portland cement, mixed by hand and 
moulded in cast-iron nifmlds of varying sizes and shapes, care being taken 
that the mixture was a wet plastic and of such a consistency as could be effi- 
ciently worked into the moulds to form a dense concrete. 

Each bkjck is reinforced with steel rods of varying diameter bedded in tlie 
concrete during the process of moulding. 

The blocks are set in a ir.orlar of ((■inciil and sand i : 2 with a steel ring 
or joint rod the entire circumference of tlic chimiuy, bedded in eac^h horizontal 
joint. Vertical reinforcement is obtained by steel rods fixed in tlie end joints 
of the blocks and furllur |)role(le(l b\ eoner<'le neckings moulded as jjart ol 
the blocks and showing as scrtical shafis on the linished slrueturi'. 

Lach vertical lod is caiTied i) It. down into ihe (■()nei'el<' loundal ion and 
there attached lo a horizontal steel ring, the full diainetei- ol ihe ehiinney at its 
base. .Spc-cial reinforcement was used round and oxci- ihe Hue opening and 
to the mrjulded corniee and neckings. 

'i'he chimney slan(i^ on a conci-eie loLnidalion slab composed of cement 
C(jncrete i : 0. 



4« 




A REINFORCED CONCRETE CHIMNEY. 



Section. 




SectionAB. 




Section EF 




Section CH, 




COP^NICE. 



CO*' «o»- ' * 




OtTAlV. O 




Plan at Base. 

Reinforced Concrete Chimnkv at Penarth. 



Detail or 
Lower String. 



+9 



E 2 



JOHX W. RODGER. 



[ CQNCBETEj 



The g-eneral dimensions are : — ^t. ins. 

Concrete foundation slab 23 6 square. 

Heig^ht of cliininey abo\e i^round 220 o 

Outside diameter of chimney al base -O ^:> 

Outside diameter of chimney ai top 10 4 

Thickness of blocks at base i ^ 

Thickness of blocks at top 5 

Weig-ht on bottom course of blocks -=8i tons jDcr square ft. 

Batter i i" 43 




N'icw of Completed Struct inc. 

KkINI 0K<;KI> C'fiNCRKTK ClIIMNKY AT Pl.NAKlll. 



At tlie outset it was realised th.ii the chimney mij^ht at times be subjected 
to excei)tionanv hi^^h temperatures, and it was deemed advisable to build the 



J, CONM kMKTIONAl. 
At^NCilNLlklNl. ^ 



A REINFORCED CONCRETE CHIMNEY. 



brick liniiii;- to within 12 ft. of the top witli a substantial air space between the 
concrete and brickwork as a special jiroti-clion to the (^oiKM'cte. 

The ])rick lininj^' is () in. thick to a hcii^lu of \H] It. <> ins. and 4^ ins. thick 
above that point, stren^tlicncd latcrail\' by buttresses projecting" into the cavitw 
No bricl>:\\<)rl>: is allowed to come nearer than 6 ins. to the concrete, as a pre- 
caution against damage to the lining by the swaying action of the chimne\' in 
a high wind. The estimated maximum deflection is 81 mm. in a gale blowing 
80 miles an hour. 

The lining is built throughout of hard red Cattybrook bricks, made to 
correct radius and set in cement and sand mortar i : 2 to the level of the bottom 
of the intake flue, and above that point to the top of the 9-in. work in mortar 
composed of ^ part Portland cement, i part slaked ground blue lias lime, and 
2^ parts sand. The 4^-in. brickwork is set in cement and sand mortar i : 2. 

The total weight ot the cliimney and concrete foundation is approximately 
1,400 tons, equal to 2A tons per sq. ft. on the subsoil foundation. 

The chimney was built under the direction and supervision of the writer, 
acting as architect for The South Wales Portland Cement and Lime Co., Ltd., 
associated with Mr. W. J. Cooper, manag-ing- director of the company. 



51 



THE CONCRETE IXSTITCTE. 



CQNCBETEi 




RECENT VIEWS ON 
CONCRETE AND REIN- jf| 
FORCED CONCRETE. I 



RECENT PAPERS & DISCUSSIONS. 



J 



It is our intention to publish the Papers and Discussions presented before Technical 
Societies on matters relating to Concrete and Reinforced Concrete in a concise form, and 
in such a manner as to be easily available for reference purposes. 

The method lue are adopting, of dividing the subjects into sections, is, ive believe, a 
neiu departure. — ED. 

THE CONCRETE INSTITUTE. 

THE DIFFERENTIAL AND INTEGRAL CALCULI FOR 
STRUCTURAL ENGINEERS. 

By W. A. GREEN, M.A., B.Sc, Eng. (St. Andrews), Assoc. M.Inst. C.E. 

The foil oic ill g is mi abstract from a Paper read at the Fortieth General Meeting 

of tlie I nstitute. 
After a few introductory remarks, the author went on to say that we cannot avoid 
definitions, and my first will be that of a " function of a quantit}^" which is shortly 
defined as an expression involving that quantitj'. Thus we may say that the maximum 
bending moment in a cantilever is a function of the length and also of the loading, and 
generally Vv'hen the relationship between quantities can be expressed by an algebraic 
e(}uation one quantity is said to be a function of the others. The symbol for 
"function" is left to the personal predilection of the writer, and may, when applied to 
the quantity ^, be/(^), ^{x), i^{x), etc. 

Startmg with two related cjuantities, which we may symbolize as x and y, we may 
express their relationship by an equation y=f(x) or x--(tAy). 

As every engineer knows, we can, by taking in the e(|uation y=f{x) different values 
for X, find corresponding values for y, and tabulate them — e.g., the safe load on 
stanchions for different hei'-;l)ts. 

A much more illuminating and often easier way of recording these tabulated 

results is to plot them in a curve, letting 
vertical distances from a fixed line 
o(iual one (juantity to some convenient 
scale, and horizontal distances to 
anotlic;r lixcd line at right angles to the 
first, the other (piantity. The two fixed 
liiKis are known as the axes, and their 
point of intersection the origin of co- 
ordinates. There are, of course, many 
other ways of representing graphically 
the relationship betw(>en the two (|uan- 
tities, but |)erliaj5s none more obx ions 
and simple. 

The C()rresi)()nding values of .v 
and V are known as C()-ordinat( s, and 
y=f{x) is termed the (;(|uatioii of llie curve so plotted. 

In the diagram (l^'ig. 1) where O.V and OV arc our fixed axes, let OA7;=-v„, 
P.,Mn—yn, Xn and y, b^;ing the co-ordinates of /^., a point on the curve whose 
equation is y=f{x). 
52 




I'K-. I. 



f7^ 



y, CONM Pllf IlONAf! 



CALCULI FOR STRUCTURAL HNCINEERS. 



TIkmi IrDin our previous dcfinilion we know that 1';/" /(v,,). 

Siuiil.'irly let the co-ordinates of i'// j i be ^n+i and .V/( + i, connected by the 
etjuation yn + \ =/(^,, + i). 

As ;i point moves alon^' the curve i'roni J^n to J^n + i in the examj^le shown, its 
distance f I oni both axes incTeases and it has moved a distance yu+\—yn up, and a 
distance .v»; \ i .v„ to th(> right. 

Pro\ idi>d this distance is small enough, its path will not diller greatly from a 
straight line whose slope is the same as the line touching the curve at J^n and called, 
for short, the tang(Mi(. 

The slope of this line can be measured by tiie ratio of its vertical travel to its 
hori;iontal travel, for a less obvious reason called the tangent of the angle the tangent 
line makes with the axis OX, which angle, for reference, we will call iK 

A short way of expressing ihe increase in the length of the y co-ordinate as the 
point moves from /^; to Pn+i is 8y, and of the x co-ordinate, ox where o is not a 
multiplier but a sign of a small increase in the quantity it comes before — o. by our 
standard notation, standing for difference. 

\\'hen 5.V and 8y are very small their ratio is termed the first differential coefficient 
of y with regard to x, and its value is obviously the tangent of ". 

\i y = ax and Xn and yn are the co-ordinates of a point on the curve, and (x-.i-rbx) 
(v, + 5y) the co-ordinates of a point near it, we know that yn—'^^n and (>';; + ^yj = 
ci{Xn-\-5y). 

5v yu + ^y — Vn a{x„ + 5x) — ax„ 8x 
5x Sx ox; 5x 

i.e., the direction of the curve is constant; or, in other words, the curve is a straight 
line which perhaps it did not need the differential calculus to demonstrate. 
Taking another equation y = ax-. As before— 

Sy ^ y^Sy — y ^ a{Xn-{-5xy^ — a{Xn)' 
5x 



dX 



5x 



a{Xn' +2x,:5x+ 5x-) — a^,r 



8x 



2ax„8x 
Sx 



adx = 2(iX,: + adx^ 



oy 



When 8x is very small its value compared with 2nX;i may be neglected, and 
2«^n, i.e., the tangent to the curve at the point whose x co-ordinate is x,, is 2<^-^;:. 

We may express it more generally by saying that for every value of ^ the first 
differential coefficient of cix'^ is 2ax, 

This statement is equivalent to saying that the slope of the curve varies directly as 
the X co-ordinate. 

As everybody knows, this particular curve is our constant friend the parabola with 
its axis vertical (see Fi^. 2) and as the slope of the tangent is 2cix, which equals 

ax- 

--,--, the tangent to the curve must halve the x co-ordinate. 

XI 2, 

Taking as our third example y = cix\ and 
treating it for the general point whose co- 
ordinates are x and y — 




8y ^ y-|_ 5y _y ^ a{X-\- dX)'^ 

8x 



-ax' 



8x Sx 

a{x'^ + 3x-Sx+3x8x'^+Sx^) — ax-^ 



Sx 



Zax-sx , 5.r-' 



{3ax-\-a8x) 



¥ir.. 2. 



8x ' Sx 
^5(ix--^8x, multiplied by an expression of 

no further interest to us, 
^3>''V- when dx is infinitely small. 

53 



THE CONCRETE INSTITUTE. 



[CDNCBETEl 



Summarizing. — The first differential coefficient 

of ax =a 
of ax'- = 2cix 
of ax-^ = 3(ix'' 
and generally oi ax" = nax»-' 

true for all values of " positi\ e and negative, including " = where ^"=1, y=ci and 



Sy 
dx 



0, which is another way of saying that a line drawn at a constant distance from 



another line makes no angle with it. 

The process of finding the first differential coefficient is known as differentiation, 

and the symbol for the operation is often written 4", t^ being the value of ^ when 



dx' dx 



8x 



both ov and ^^ are very small. 

The values of the first differential coefficient can themselves be plotted to form 
another curve, and the process of differentiating continued ad lib., the first differential 
co-efficient of the first differential co-efficient of the original quantity being termed, for 

short, the second differential co-efficient, and written ^ which indicates that the 

ax' 

operation has been twice repeated. 
dx 

Similarly, - need have no terrors for a reader if he is not expected himself to 
dx'^ 
repeat the operation n times. 

Perhaps one of the most valuable uses of the difterential calculus is the location of 
maximum and minimum values of a continuously varying quantity. 

On each side of a maximum or minimum there are two equal values, and at the 
maximum, as in water-level at high tide, there is no change in one quantity as the other 
varies ; in other words, the first differential coefficient is zero. 

Reverting to the small increment Sx, let us, instead of examining its relation with 
the small quantity or, discuss it as a multiplier of y. 

ox and y bein? both represented by lines, their product ySx is obviously an area, 
viz., that o^ the rectangle with base 5^ and height r. 

In Fif(. 3, if the line MaMb, the projection on OX of the portion of the curve 
y = f(x) between the points Pa and Pb, is divided into a number of small lengths, Sx, the 
area of the figure, J'aMaMhPh, is greater than the sum of the areas of the rectangles of 
area yox by an amount ecinalling the sum of the small triangular figures each of area 
^ox y'oy, when ox is small enough to make the portion of the curve of which it is a 
projection, a straight line. 

We may write this eciuation symbolically: — 



x=b 



Area PoMaMhPo^ 



2r^.v+52 



oyox 



where - — the Greek S stands for the sum 
of all such (|uantities at yox and oyox which 
follow it, x = a and .v /; indicating the 
limits between which the summation is 
made. 

When oy is infinitely small, each of th(> 
terms yox is infinitely small, but as there 
will be an infinite number of tlicin the sum 
will he. a finite quantit>'. 

The |)rodiict, however, of (wo infiiiiteK 
small (juantities will bf; infinilel\- small 
compared with either of lliem, so that even 
if an infinite number of tli<iii are taken the 
sum will be infinitely small. 

5 + 




I'lC. 3. 



y, CTON> ryut-noNAiJ 

<^ ENGJ N LluR 1 M » — J 



CALCULI FOR STRUCTURAL ENGINEHRS. 



Th(> last term (^f our ((iiialion ^^ill therefore vanish, and the area may be 

oxi")r(^ss(>{l as : — 

. h 

x-a 

where an old l'nt;lish / is nsed for the summation sign, and an English d is substituted 
for the Greek 5. 

This summation is termed integration. 

There are, however, dithculties in the wa\- of 
plotting curves and measuring areas, and a further 
in\ estigation is necessary. 

The shaded area in the diagram (/''/^^ 4) increases 
as X increases. 

Let the increment of x be ^x and the correspond- 
ing increment of the area be ^A. 

Then when Sx is verv small 5 A =ybx 
M ' . dA 

or the first differential coefficient of A=y ; 

but .4 = / ybx the 
-^ o 

integral of y with regard to x. 

i.e. if A is the integral of r with regard to x. 

Fig. 4. y is the differential of A with regard to x, 

so that integration and differentiation are inverse 

operations. 

In differentiating f{x) with regard to x we find the relation between ^x and oy at a 

point whose co-ordinates are x and y. In integrating f{x)bx by finding an expression 

whose first differential ccet!icient is f{x) we find an area of the figure enclosed between 

the curve, the axis OX, the axis OY, and the vertical line through the point xy. 

If we wish to integrate between two limits, e.s;- from x = a to x^b as in the previous 

illustration — we can subtract the integral from ./^O to .r = a from the integral from 

.r = to x = h. 




We may tabulate our integrals as we tabulated our differentials — 

adx =ax 

I 2axdx = ax' or f axdx = 
I 3ax'-dx = a.r'' or J a/'dx = 



As — ax =a 
dx 

as — ax —2ax 
d.r 

as — ax =5ax- 
dx 



ax- 

T 

ax'^ 



and generally 



as -^ ax'^ =nax'—'^ 
dx 



fax 



-^x = d 

n 



The above results satisfy our condition that the integral of a function is another 
function whose differential is the original function, but to make the statement complete 
we must add a constant to each, the value of which can be found later and may 
be zero. 

This constant will satisfy our condition as — 

— constant = and .'. / 0<^f^ = constant. 
dx -J 

Just as we could repeat our differentiating operation to find the first, second, third, etc., 
differentials, so we may repeat the reverse operations to find the first, second, third. 

etc., integrals so that the sign / / is really not so terrible as it appears — 



55 



THE CONCRETE INSTITUTE. 



LCQNC^TE 



e.g. fodx =C^ 

JjQ,dx'= f ^\^^ 
Odx'= J J C,dx 



C,x-\-C, 



f {C,x-^-C)clx= ^ H-CVv + C,, etc., 



the Iruth of which statement can be verified by differentiating the last expression three 
times and arriving at zero as our final result. 

It is unnecessary here to evolve from first principles the equation /= where the 

letters have the significance set forth in Hie last word in standard notation — 

/= intensity of fiexural stress at extreme fibre 

« = distance of neutral axis from extreme fibre 

7^ = bending moment 

/ = inertia moment. 
It may not, however, be out of place to examine a small element of length ox of a 

deflected beam a distance ^ from some arbi- 
trary origin whose neutral axis has been de- 
flected a distance y from some arbitrary base 
line through the origin {Fig. 5). 

In the length Sx let the inclination with 
our base line vary from the angle d to the angle 
(e-\-80), where ^ is measured as the ratio of 
the circular arc it subtends to the radius of the 
arc. 

When an angle is small the difference 
between this ratio and the tangent of the angle 
is negligil)le, so that 86 is the ratio of the con- 
traction of the length 8x at the top of the beam 
under the stress / to the neutral axis distance //. 
A stress E (the modulus of elasticity) would 
make ^^ contract an amount Sx if something 
else did not happen first, so that/ would make 

fdx 




Fig. 5. 



fox 



it contract -^ , and the angle 50 may be expressed as 



If, as is usually the case in structural engineering, ^ itself is small, its value is 



dy 
dx 



so that — 



but -r also equals r^, 
dx hn 



86 d dy d'y, 
ox ~ dx cix~ dx- 




d-y f lln I 
dx-'~En~ I ^En 


E 
~BI 



In the e(iuation — ^ = ,,, 
dx' HI 

we see on int(.'gratiii;-,' that , = / ...dx-\-C\, 

i.e. the slope of the curve at any point x from the origin can be measured by the area of 
the bending moment diagram, the value; of the constant C, depending on circumstances. 
Integrating again we obtain the {l(;fl(!clion curve of the neutral axis as — 



-ff^, 



dx''-\-C,X'\-C.,. 



Deflection, slope, bending moment, shear, and loading, may be expressed as a series, 
in terms of any one of them. 



56 






CALCULI I'OR STRUCTURAL HNGINEERS. 



I'siii^' hi'iuliiii; inoiiuMil ;is our hasis 
III X DtMlertion 



7:7 N Inrlinalioii 



HeiidiiiiT niouicul /•-/ , .=/> 



C, 



Sh 



iiiy=J f iui.r--VCyi-\-c., 

Ll'' - flU. 
(I.I J 

if'v 

</ 



Lo&d DtiU^rAm 



0.1 r 



Loading 



</'v d'B 
f/.r ax 




Fig. 6. 



for such part of it as is a function of '■. 

From the above series it will be seen that deflection bears the same relation to 
bending moment that bending moment does to loading, so to draw a deflection curve one 
has simply to draw a bending moment diagram for the original bending moment diagram 
considered as a load diagram. 

Another problem presenting difficulties to many engineers is that of internal shear 
which, with the aid of the calculi, we will attempt to investigate, making the usual 
assumptions regarding a plane section before bending remaining plane in bending. 

Consider a small length rf.r of the beam cut by two sections normal to the neutral 
axis — at distances x and x+5x from the origin. 

Take a section parallellto the neutral axis at a distance a from it. 

_B2i 

At X from the origin the extreme bending stress— j ; 

at ./-r^./' from the origin the extreme bending stress = 

where B and [B + ^B) are the bending moments .x: and .r + ^.r from the origin. 

The total horizontal shear on the horizontal section w^y^^x a distance a from the 
neutral axis equals the difference between the thrust to the right on the part of the 
vertical section above a, x from the origin, and the thrust to the left on the part of 
the vertical section above a, x-\-5x from the origin. 

This thrust difference may be expressed — 



{B-\-m)n 



n n 

J W zfSz LP JxCz (/+ 5/) ^Z , 



where ^z is the width of the cross-section z from the neutral axis and f and /-r ^/ are 
the horizontal stresses there x and x-}-5x from the origin. 

' B-\-SB 



Then as ~ 



B , nsf 

- and ^ 

/ z 



I 



the total change in horizontal thrust — 



B 



w —z^z cr / "'■c 



B + 5B 



z^z 



= / ZOZ ^ — / WZdZ 



= — X (Area moment about the neutral axis of that part of 
■* the vertical cross-section above the horizontal 

section a from the neutral axis). 
This shear or change in horizontal pressure in the distance 5x is on a horizontal 

area WaXdx, so that the intensity = (Area moment of that part, etc.), i.e., shear 

li'aOXl 

intensity = -^^- X (Area moment, etc.), as S the vertical shear =-- • 
icl dx 



5' 



THE CONCRETE INSTITUTE. 



[ CDNCBETEJ 



Consider a reinforced concrete beam (see /''/^<. 7) assuming no tension in the 
concrete — 



/= / zhzdz-\-ni X steel area X (cf — ;/) - 



= ^ + ;;, X steel area x (J - n) "' , 
3 



the letters having the standard significance — 



hn' 



= m X steel arei x {d — n) 



n#rji-.^At A^iS i 



n 




and shear intensity, a maximum at the 
neutral axis — 



Cross Section. Shear Intensity. 

Fig. 7. 



As the stress in the steel x distance to centre of compression y^~y equals B, the 
change in stress per length Sx — 



dx , n 



S 



'-5 '-3 



and the shear intensity per unit area 



{-3) 



the same as the concrete shear in- 



tensity at the neutral axis, so that the theoretical internal shear is constant below the 
neutral axis and decreases to zero in a parabolic curve above it. 



THE WESLEY AN METHODIST HALL, WESTMINSTER. 

By H. V. LANCHESTER, F.R.I.B.A. 

The following is an extract of a Paper recently read before the Royal Institute of 
British Architects. In an earlier issue of this Journal the Wesleyan Hall isjas fully 
described as far as the reinforced concrete construction was concerned {see Vol. V., 
p 721). Our extract has been taken from the Journal of the R.I.B.A., Vol. XXL, No. 2. 
In his ojjcning remarks, the author stated that there were a number of problems in 
the design of this building, the solutions of whieh jn-esemt a certain degree of novelty 
and may be of interest to architects. 

After making reference to the comixlilion instiluled to |)r()curc dc signs, the diHuiilty 
of planning and arrangement ar(; dealt with. 

'J'he author set out the accommodation the hall was to contain; lie also described 
the difficiillies to be overcome in the construction of tlic main staircase. Hrielly, the 
princijjal requireuK-nts of the building were: — Largt; hall, seating 2,500. Small ludl, 
switing 600. Library of the same size (these two to be thrown together on occasions). 
Conference hall. A room of the same size (now occupied by the London City and 
Midland Hank), 'i'ea room to s<'al j,ooo. I'"our committee rooms. A block of oHlces. 

Leaving the minor deUai Is of |)lamiing, he passe<^l on lo the nielhods of consilriiction 
emjjIo\(fl. Reinforced work has been exte^nsivcl)' use<i in the interioi,, for the reason 
that it ']>> more homogeneous than -any of tlw; combinalions of steel rollings with 
concrete and other materials. 'I'lie architects' choice fell on the Kahn system as 
j)roviding a bar th.at once in }K>sii'ti(>n was visibly adjusted lo take uj) the .strains 
provided for before Hlling-in comuK-nced. Of cour.se, there are other systems that 



,CONMKM)C riONAl 



W'liSLEYAN MHTlloniST HALL, WESTMINSTER. 



;n liir\<- this ^liin, hiil not the slij^hli'^t i^round could he found to rc^^rd llir M-l<-(lion. 
IiuK'i'd, the onh i)i>inls where slij^lu iracUs li:i\" sliow n tliciiiscKcs ;ii-<- when-, in 
order to eeniioniise <lt|)lli, strel .sections \\<'re resorted to. 'I'lie aullior tliou^ht it 
desirabk' to w.iin some ol those present thai I hi' puhhshed streni*tlis of steel beams 
are not rehahle ; tlvou.-^li the) are well within the liniil of siifoty, j^reaK-r de|)th must 
healUmcd w heie the slii^hlest dillection will disturb the work abov<' them. 

In th<' i^ene'-al framing:: up of this building the hea\ iesl weii^hl aeeunuilaied at 
the eij^ht ani>les of th<- main dome. Startini; from the to|), we have the outer dome, 
a n"lativil\- lii^ht shell, the much heavier concrete inner dome, the concr»-te and 
masonrv of the i)endentiv<'s and the arches across the trans<'ijts ; then the j^irders 
carrvinj; the ox crliai.i^in.L; i;alleiies, a i)r(>p{>rtion (^f the walls and floors below this, 
and, Iniallv, the w<"ii;ht of the i)i<M-s themselves. With allowances for wind pressure, 
<'tc., the weii^lUs r(>achini; the foundations at each of these jioints ranj^e from 500 to 
600 tons, and as it was, of course, desirable to equalise the weif*ht as much as possible, 
a stec^l raft was j^rovided under each pair of jiiers, which j^ave a distributed weii^ht 
of 2 tons to the foot super. Under the w hole of the remainder of the buildinLi ^vas a 
reinforce<:l concrete raft of varying thickness, and the weight on this generally was 
about i^ tons per foot super. The eight main piers were formed of steel sections, 
at the angles of a 3-ft. square, tied together with stec^l lattice-work, and entirely 
<'ncased and filled with ceir.ent concrete. The architects themselves worked out the 
meth(xls of construction in these, but throughout the rest of the building they were 
indebted to Mr. de Colleville, then with the Trussed Concrete Steel Company, for 
checking calculations and supplying details of connections, ri vesting, etc. The remain- 
ing piers were of reinforced work with vertical bars and horizontal lacing. The 
basement floor is 7 ft. above the bottom of the concrete, which gave the requisite 
depth for distributing the weight under the heavier piers and for the provision of 
ventilating and pipe ducts. The large spaces on the basement floor were covered 
with thin reinforced concrete vaults, carrying a flat floor about 8 ft. aboAc the street, 
which is the ground floor of the main building. (The floors of other parts are at 
different levels.) The flcx)rs above this are constructed i>f reinforced concrete, with 
hollow tiles to reduce weight. 

The galleries demand some description. They are nuiinly supj)orted by deep 
girders connected to the lattice stanchions ; these form the fulcrum from which they 
cantilever forward, while the back is built into the main walls. The ramps pass over, 
and the sofilits under, these main girders, so that the cantilevering does not entail 
excessive weight. 

Over the galleries are the transept vaults, ellipticid in form, and thicknt-ssed into 
strongly reinforced beams under the vertical walls of the outer dome. From these 
beams and the pendentives springs the coffered inner dome of reinforced concrete, 
with two rings of steel plate to resist the outward thrust. 

Although the Large Hall is 70 ft. in height, its dome would hardly be visible 
from outside; and the outer dome, relatively light in construction, rises some 50 ft. 
higher, exclusive of the lantern above it. As the design based itself on the conception 
of a square dome with the angles cut off, forming an irregular octagon, necessarilv 
special constructive requirements had to be met. A circular dome is relatively easy 
to construct, there being no tendency to distortion ; but all other forms have an inclina- 
tion towards the circular, a straight-sided dome tending to bulge horizontallv between 
the angles. The first step was to provide at the base a plate of great horizontal 
rigidity firmly tied at the angles. As the weakest points were towards the middle of 
the four long sides, the ribs were treated in this position as principals tied right 
across; these are in pairs, connected together at the top with a braced ring, which 
carries the lantern and links up the angle-ribs, which are also braced on similar lines. 
These ribs and the intermediate ones carry the steel purlins and timber rafters of the 
dome covering. The lantern is mainly of timber construction, but stiffened bv four 
steel ribs steeply inclined at the four angles, these ribs carrving the finial rod, and 
torsion IS guarded against by a horizontal bracing near the top of the lantern filled in 
with cement concrete. 

The lecturer closed with some remarks regarding the engineering requirements 
and the architectural treatment. 

59 



NEW WORKS IN CONCRETE. 



ICDNCBETEI 



NEW WORKS IN CONCRETE 

AT HOME AND ABROAD. 

Under this heading reliable information ivill be presented of neiv -works in course of 
construction or completed, and the examples selected 'will be from all parts of the ivorld. 
It is not the intention to describe these -works in detail, but rather to indicate their existence 
and illustrate their vrimary features, at the most explaining the idea 'which ser'ved as a basis 
for the design. — ED. 



A REINFORCED CONCRETE MOTOR GARAGE, WHITBY. 

The accompanyinff illustrations show a motor garage recently erected at Whitby. The 
structure is a concrete-frame building, with 9 in. brick walls around the garage and 
II in. cavity brick walls around the house. The columns and beams to the front of 
the building are moulded reinforced concrete. As will be seen from the accompanying 




■i MH 






■:>-."j!» ■m'^'*?' 




View of Completed Structure. 

RkINIORCKU CoNfRKlK MoKjK fiARA(.I., WllITHY 



plans, in addition to the nujtor garage, th<' following rooms IikIvc been provid<Hl, namely, 
a drivers' room, workshop, woodwork shop, lavatories, and showroom. 'Vhv hous(> 
adjoining consists of two floors, comprising silling-room, cnir.incc h.ill, store, kilcheii, 
scullerx , and ff)ur bedrooms and a l)athroom. All the lloors are of reinforced concrete, 
whilst the rof)f is covered with asbestos tiles. I"\irther, the staircases are also built in 
concrctf-. 'liie rontractors for Ibis building were Messrs. (ieorge Greenwood Sons, 
of New Brunswick .Sfrr-et, Halifax, who carried out the work' on the Rigid S\stem of 
reinforcement, according to drawings supplied l)\ Ilie Rigid keinforcement and 
Concrete Rnginer-ring (Jo., Ltd. 'I'he architect was .Mr. Harold (i. Walker, of VVhitb\ . 
We are indebted to .Messrs. Greenwood .Sons for our |)articulars .tnd illustr.ilions. 

60 






REINFORCED CONCRETE MOTOR (PARAGE. 











t o 



c^ 





o 



NEW WORKS IN CONCRETE. 



1^^^^ 



REINFORCED CONPRftr- d a ^^ 

"""* " ■• " "■" ■■■ i.« .'■ .,-..i«„ „„,,, ,,. ,, 




is also a 
62 




.'ind ;i /lew f,-i((or\' ;ii \r(lcn VV'fnl-. • 

lhr<M;.storcy building ' •'l'l""^"".M.K ., ,„ f,. I,v .,„ f, 



^\ i'i'', which 



y, tX>NMDlR~TIONAi; 
A bNQl N JAU 1 N( I — , 



REINFORCED CONCRETE FACTORY EXTENSION. 




z 

< 

J 
a 






z 

luO 

UilL 



Z 



UlUj 

=^ 

Lua 



<o *■ 






« a 






63 



NEW WORKS IN CONCRETE. 



ICDNCBETEJ 



The site for the new pahit shop bcinj^ on ;in old clay j)it, filled in with rubbish, it 
was found that ordinary concrete footini^s would not be satisfactory. 

After a number of tests had been made to ascertain the carrying capacity of the 
earth, it was decided to adopt a reinforced concrete raft, which would evenly distribute 




the load over the whole of the site, pnllin;.^ a ma.\iniiini pressure of a lillle oxer i cwt. 
per square foot cm the fcjundatioii, 

'J"he building is a steel frame shu<line with ibiii (iiii.iiii walls, so thai I he whole 
of th(; loads are coiK eufrat( d at |)oints 25 ft. from (entie to (eiitie in the olhei. 

64 



fTT^NM^wiKTioNAq R]^:iNr()RCt:i) concrete factory extjiNsion. 



From llif i>l;in it will be scs'ii that the raft consists of a conlimious slab, rov<rin^ 
the whole of tlu' >itr, and s|)ainiini^ bclwoi-n the inverted beams, which, in turn, span 
between the eoluinn marked " ('." 

'I'h<' lop surface of the slab was finished with a i^raiiolilhic face and forms the 
i<round lIcKir of the factory. 




The suspended floors at the new factory, Arden Works, and the flat roof at the 
paint shop were constructed in hollow Siegwart flooring. 

Part of the floors were constructed to carry a live load of 6 cwt. per foot suj^er, and 
the remainder i^ cwt. per foot super, while the flat roof was constructed to carry f cwt. 
per foot super. 

F 2 65 



NEW WORKS IN CONCRETE. 



(Concbete: 



The great advantage claimed for the Siegwart flooring is that no centring is neces- 
sary, and so the work, in sitUt is reduced to a minimum. 

As will be seen from the accompanying illustrations, the hollow beams are brought 
to the site in a thoroughly matured condition, ready for fixing. 

These beams are placed side by side on the supporting steel joists and the joints 
then grouted in with cement mortar when the floor is fixed complete. 

The architect for this work was Mr. J. J. Hackett, M.S. A., of Birmingham; the 
contractors for the reinforced concrete raft were the Empire Stone Co., Ltd., of London; 
while the floors were carried out by the Siegwart Fireproof Floor Co., Ltd., of London. 




Fit^. I. 



ml .1 f;(;iiient. liti-2. Finished Post. 

Kl.lNI OKCI.I) ("oNf KKIK I, AMI' PoSTS. 



REINFORCED CONCRETE LAMP POSTS. 

Cai'IAIN I). C)(;ii,vY, Assistant Conimandiiig i\o\aI l^ngiiiccr, Ahiucdnagar, Dcccan, has 
recently designed and construct<'d a type ol reinforced concrete lamj) |)os(, which, for 
simplicity of design, f,'icilit\- of manufaclure, and low cost will he welcomed by i-ngineers 
to small urban councils at home and in I he ("olonies, ;ind to cantonuKMit authorities in 
India. 

The accomf)anving four phologiaphs will, it is hoped, make its general design and 
mode of construction clear. 

Fig. I shows the armouring, whieh ( onsisls of four mild st('<'I roads, ;' in. diameter, 

66 



r J, c-oNyruucTicMAn 

L<v ENGJMEEJglNCi -*3 



RHINFORCHD CONCRETE LAMP POSTS. 



suitahlv lied witli ,-'« in. (liaiiicl(>r bracelets. Tlif jji-ojcrtin^ arms (to support a " lamp 
lij^litcr's " ladder) have a dovihle reinforfenieiil of ^\ in. or .', in. diameter rods. The 
l)oll which se(iir<s the famili.ir lamp ( radic is aKo sjiow ii, also four extra i in. rods are 
i^ivi-n where the plinth nierjLjes iiilo the main (oliinin lo resist anv undue transverse 
stiains durini^ <'rection. 

hi'o, 2 shows the fmislKnl jxyst. Its cost, fixed in |)osition, is 12s. ConK-nt cost 
us. per barrel (400 lb. not), and mild steel rods 10s. ])er cwt. 

h'igs. 3 and 4 show the moulds, whic h consist of { in. mild steel plates, each taking 




Fig. 3. Moulds with and without Reinforcement. 




Fig. 4. Moulds tilled. 
Reinforced Concrete Lamp Posts. 

two posts laid head to foot. The shutterinj:^ of i in. Burma teak are fixed down by iron 
straps and bolts to these pallets. As the post plinth is 7 in, by 7 in., and the column 
5 in. by 7 in., the reduction of 1 in. is effected by telescopinj:^ side shutterini^ and by 
fixing a I in. plank underneath the column. 

The proportions of cement, sand, and ai^j^rei^ate are i to 2 to 4 (bv volume). The 
sand is a finely i^raded quartz. The af^ijrei^ate, which is graded from f in. to | in., is 
shingle obtained from neighbouring ravines, consisting of manv kinds of igneous rock. 

67 



NEW WORKS IN CONCRETE. 



rCQNCBETEJ 



CONCRETE BLOCK HOUSES AT NEWBURN-ON-TYNE. 

The accompanying illustration shows; j^art of twenty-four concrete block houses 
in course of erection at Newburn-on-Tvne bv Messrs. The Blaydon District Industrial 
and Provident Society, Ltd., for their members. This Society liad already erected 48 
similar houses at Blaydon-on-Tyne and these were so readily taken up it was decided 
to pnx-eed with a further number. 




C()>iCRL'LL Block Houses at NK\vbuKN-ON-TvNE. 

The houses vary in size, havinj:^ sittinj:^-room, kitchen and scullery, or combined 
kitchen and scullery, two, or three bedrooms, bath-room with hot water system and 
conveniences in yard, and vary in price from ;^5oo each downwards. 

The houses were designed by Mr. Wm. Crooks, Junr., Architect, Blaydon-on- 
Tyne, and are built throughout with blocks made on one " Winget " machine purchased 
by the Society. 



68 



j,coNMk>ufriaNAi; 



NEW BOOKS. 



NEW BOOKS 

AT HOME AND ABROAD. 

A short surnmjrv of some of the lejdtnq books tuhich hj've appeared during the last fcu) months. 



The Glasgow Text Boohs. Edited by G. 
Moncur. 

"Reinforced Concrete Railway Structures." 
by J D. W. Ball, Assoc. M.inst.C-E.. 
A.C.G.I. 

London: Constable and Co., Ltd., 10. OranKe Street, 
Leicester Square. W.C. 213 pp. + xiv 1913. Price 
«/- net. 

It is sometimes said that of all British 
enj^ineers, those who control our railways 
have been the most reluctant to adopt re- 
inforced concrete. Mr. Ball in this work 
gives reasons for this cautious attitude, 
and he wisely advocates its use in the best 
possible way — not by preaching reinforced 
concrete in season and out of season, but 
by showing where it is of the greatest 
service to the railway engineer, and, on 
the other hand, where its older rivals still 
hold their own. After reading his book 
one is struck with the variety of ways in 
which reinforced concrete can be used in 
railway work with the greatest con- 
venience and with true economy, , 

In the first chapter, on " Preliminary 
Considerations," this question of the con- 
venience and economy of reinforced con- 
crete is discussed, and an interesting com- 
parison is given between a floor designed 
as a reinforced concrete Tee-beam and one 
designed in the older manner with steel 
joists and concrete filling. Estimates of 
costs are given in each case, which show 
a clear advantage in the newer type of 
construction. In the same chapter the 
quality of the component materials — 
concrete and steel — and the permissible 
stresses to which they should be subjected, 
are briefly dealt with. 

Chapters 2 and 3 deal with the theory 
of Bending and Shear Stress, and contain 
a really useful enquiry into the subject of 
the most economical proportion of steel to 
concrete in a beam, having regard to the 
actual costs of these materials. 

Chapter 4 deals with Floors and Build- 
ings, and incidentally gives an example of 
a floor reinforced with old rails. On rail- 
way works this is a cheap form of steel, 
but it should be pointed out that if rails 
are used careful investigation should be 
made into the bond stresses, as rails are 
weak in this respect and difficult to anchor. 
Chapter 5 deals with Foundations and 
Rafts. One of the most useful applica- 



tions of r('inforc<'d concrete is in the for- 
mation of rafts or foot-blocks under heavy 
walls and columns, and the calculations 
required to design such rafts are given at 
some length. 

Chapter 6, on Retaining Walls, will be 
of great interest to railway men. It is 
pointed out that in many cases the old- 
fashioned gravity wall will prove cheaper 
than one made with reinforced concrete. 
The necessary calculations for the strength 
of L-shaped walls are given and explained. 
The stability of this type of wall is also 
touched upon. But it is curious that this 
work, like so many other text-books on 
retaining walls, omits altogether to con- 
sider the most common weakness of all 
these structures, viz., their tendency to 
slide forward on their bases. An L-shaped 
wall, with its horizontal limb turned out- 
wards, is described, and it is shown that 
it is secure against overturning and 
against crushing the ground beneath it; 
but nothing is said about its tendency to 
slide forward, and this wall certainlv 
would do so if built on a slippery founda- 
tion. 

Chapter 7, on Bridges, gives nianv inte- 
resting examples and an original investiga- 
tion into the stresses induced in beams 
with sloping ends, such as are commonly 
used for station footbridges. An example 
of a railway underbridge is very briefly 
described, so briefly that the reader wishes 
for some further information on this type. 
Chapter 8, on Arched Bridges, contains 
complete calculations of the stresses in 
two-arched overbridges of 40 ft. span. 

The last chapter, on Sleepers, Fence 
Posts, etc., contains a most interesting 
enquiry which the author has made into 
the subject of the stresses induced in rail- 
way sleepers, and explains the difticultics 
attending the use of reinforced concrete in 
their manufacture. 

We are disappointed to find that the 
author has not adopted the standard nota- 
tion put forward by the Concrete Institute. 
It is a great help when the symbols used 
are familiar to the reader, and we hope 
this defect will be remedied in later 
editions. We should like also to see the 
subject of live loads more fully dealt with. 
The efl"ects of heavy rolling loads, and the 

69 



NEW BOOKS. 



igONCBETEi 



provision that should be made against 
them in the way of shear and bond 
strength, are subjects of the highest im- 
portance to the railway engineer, and 
deserve a chapter to themselves. 

The book is well illustrated, and, besides 
giving prices, in some cases the author 
has added extracts from the specifications, 
which will be found of service. We feel 
sure that this is a work which will be read 
with interest by every railway engineer, 
and especially by those who desire to study 
what has been accomplished in reinforced 
concrete. 

*• The Strength of I-Beams in Flexure." By 
Herbert b . Moore 

Published by the University of Illinois Arban i. European 
Agent, Chapman & Hall, Ltd., London. 40 pp. 
Price 20 cents. 

Contents. — Phenomena of Flexural Failure 

— Earlier Tests of I Beams — I Beam 

Tests at the University of Illinois — 

Yield Point of Structural Steel in 

Tension and Compression — Failure of 

I Beams by Direct Flexure — Inelastic 

Action of I Beams under Low Stress — 

Buckling of Compression Flanges of 

I Beams — Tests to Failure of Beams 

Restrained from Twisting of Ends 

and Beams Restrained from Sidewise 

Buckling — Effectiveness of Sidewise 

Restraint of I Beams — Web Failure of 

I Beams — .Stiffness of 1 Beams — 

Summary. 

These notes are published in the form 

of Bulletin No. 68 of the University of 

Illinois, and are an addition to the useful 

literature that has already been published 

by the University dealing with the research 

work of the department which is under the 

supervision of Professor A. N. Talbot. 

The various tests that have been made 
are important, as they deal with a form 
of member which is so extensively used, 
and they have been conducted with a 
variety of method that is likely to cover 
those conditions which obtain in practice. 
The author states in the .Summary that 
the separators commonly used between the 
webs of I beams do not furnish a stiff 
bracing against sidewise buckling, and 
great stress is laid on tlu importance of 



regarding the yield-point strength and not 
the ultimate tensile strength, as the ulti- 
mate fibre stress for structural steel in 
flexure. The various tests are clearly 
explained and presented in such a manner 
that the results and recommendations are 
readily available to the reader. The notes 
and tests dealing with beams which were 
restrained are of particular interest, and 
we have no hesitation in recommending 
this little book to our readers. 

" Handbook of Structural SteelworK." 

Redpath, Brown & Co., Ltd., 1913. 

This handbook gives in a convenient 
form the necessary general and detailed 
information required in the designing of 
structural steelwork, and will be found 
most useful to <all those interested in the 
subject. The book is arranged in parts, 
each having a contents page and contain- 
ing notes and formulae explaining in 
detail the tables to which they refer. 

Part IV. contains a very clear explana- 
tion of the main principles of steel struc- 
tural design. 

Part V. gives suggestions and details 
of construction with standardised connec- 
tions, and by attention to these in design- 
ing steel buildings considerable economy 
may be effected. A selection of compound 
girders is given obviating the making of 
numerous minor calculations. 

In compiling the parts attention has 
been paid to the Acts governing steel con- 
struction. 

The whoU' of the definitions given are 
very ck-ar and easy to follow, and the 
various tables are well arranged. 

" ClerK of WorKs " 

G. Mctson. Price 2/6. 

'I'his handbook deals with the duties of 
a (]l<'rk of Works. It will be found of 
great help, chiefly to those taking up the 
position of Clerk of Works for the first 
time, 

Tliosc wilh previous experience of the 
(hiiic-^ will i)rolial)ly gain some valuable 
hints from reading th<' book, which in- 
structs and also niak<'s cU'ar what is re- 
ciuin'd of an <iricient Clerk of Works. 



70 



A KNdlNl 1 l^lNd — ^J 



MEMORANDA 



ii.iiiH|iili|iiii 




MEMORANDA. 






i 



Memoranda and Netvs Items are presented under this" heading, with occasional editorial 
comment. Authentic netvs iiyill te tvelcome.—ED. 



The Concrete Institute.— A paper was read last month by Mr. Lawrence Gadd, 
entitled " Some Fallacies in Testing Cement." A report of the paj)er and discussion 
will be j)ublished in our next issue. 

Newcastle Civil Engineers Students' Association. — An interesting address was 
some time ago delivered at the opening of the winter session of the above Association by 
Mr. C. H. Sandeman, M.Inst.C.E. In the course of his remarks the lecturer referred 
to the atmospheric influences on concrete. He stated that its failure in sea water in the 
past had been due to incorrect proportioning and mixing. Very great care was necessary 
in the measurement of proportions, and in the quantity of water used. Unfortunately, 
despite an improvement of late years, there was still a great laxity in these respects, and 
one was inclined to fear for the future of some important sea works now being 
constructed. 

No other material, he concluded, offered such complete protection to iron and steel 
as cement, and no material was more permanent than properly made concrete, so that he 
looked forward with confidence to the extension of its use, in intimate combination with 
steel, in almost every class of engineering structure. 

Fourth International Congress of Building and Public Works.— We are 
asked to announce that this Congress will take jjlace at Berne, August 23rd to 27th this 
year, under the auspices of the Swiss Federal Government. It is hoped that the Con- 
gress will be a thoroughly representative one, as important questions will be brought 
forward for discussion. A full programme will be issued by the Organising Committee 
at a later date. The headquarters of this Committee are at 13, Seidengasse, Zurich. 

Fire-Resisting Concrete, — Of recent years complete confidence has been estab- 
lished in the fire-resisting qualities of properly constructed concrete, says the Canadian 
Engineer. These, combined with its durability and strength, render it particularly 
suitable for the construction of buildings in which more or less hazardous occu])ations 
are to be carried on, or which are to be erected in areas wherein it would be difticult to 
cope with a conflagration. 

For fire-resisting concrete quartz sand should be used, and broken trap rock is, 
perhaps, more suitable than any other substance. Limestone is probably next in order 
of suitability, although it will eventually run into a crude form of glass or be calcined ; 
but that will not take place until the cement itself has been disintegrated. Contrary to 
the commonly received opinion, cinder concrete is not unsuitable from a fire-resisting 
point of view. The chief objection to its use is that it is far from strong. Heat does 
not affect it to a great extent; indeed, it has been found that small pieces of coal 
embedded in concrete have remained entirely unaffected by heat. That was due to the 
low heat conductivity of concrete; indeed, it might almost be said that it is an insulator 
of heat — so much so, at any rate, that the hand can be borne on the top of a slab of 
concrete 5 in. in thickness under which a fierce fire has been raging for five hours or 
more. 

This non-conductivity is well shown by the following account of a steam conduit 
built of concrete. The conduit was about 500 ft. long, and was built between a mill 
and a boiler-house, and was made just wide enough to take two steam pipes 6 in. in 
diameter and two smaller pipes. After the pipes had been laid in position a concrete 
•cover was constructed over them, so as to render the conduit proof against any moisture 



71 




CDNCEETE^ 



CONSTRUCTIONAIT? 
BIVGINE.ERI'NG 



iw 




^x>=^^=^ ^^>-^^i=^ h>=^b>ocj ^o^.^j:^.<:^^^ bc-=^^=:^ k^^jj::^ t:o..^i=»<xr^^^ 



t\ . 



Y 



Automatic P iling Hammers 

^=^=^^=^=^^^^^= (Patent) ^=^=^^^=::^=^I= 

IF YOU WANT TO DRIVE YOUR PILES 
QUICKLY YOU MUST HAVE THIS HAMMER 
—ITS THE ONLY ONE THAT WILL DO IT. 



These Hammers 
give from 500 
blows in the 
smaller sizes to 
200 blows in 
the larger sizes 
Per Minute ! 




You just open a 
valve and watch 
your pile go 
down. There 
are no springs, 
levers or cams to 
get out of order. 



MADE IN VARIOUS SIZES SUITABLE FOR 
THE LIGHTEST TIMBER SHEETING OR THE 
HEAVIEST PILES. THIS IS THE SIMPLEST 
PILING HAMMER ON THE MARKET, HAVING 
ONLY TWO MOVING PARTS. ONE OF WHICH 
HITS THE PILE-:. IT IS ABSOLUTELY SELF- 
CONTAINED, AND WORKS EQUALLY WELL 
ON STEAM OR AIR. 

Sent on Seven Days' Free Trial to any Contractor 

A/j. I'Airricui.Aus and i'atai.ocuf.s from 

THE BRITISH STEEL PILING CO., 

DOCK HOUSE, BILLITER STREET, LONDON, E.C. 

Telephoiif; 5U>i AVKNLI.. I - I. )ii;iiiis— ' I'lI.INCiDOM lEN," LONDON. 



I 



.>.==ii^ h-^^xj \.^^M y^> ^r.^ k-^~4i^^- n^ V>-^-A \^^^r^ \-<=^^PM \^>'=^^^ 



72 



Please rnenlion this /(xirrul •luheri •writinq. 



c»,coNyiknic-riONAi3 

fi KNC.INK t PtNd — J 



MEMORANDA 




4'Z. Id-It' 
Four Forms of Cutting Edge for Concrete Caissons. 



in I he >()il or surface water. The eonduit was carried some 2 ft. 6 in. below the surface 
- not sulVicieiitly deep to he beyond tlie inlluence of the specially heavy frosts which 
were periodically experienced in the neif^hbourhood in which the conduit was laid. The 
concrete trou.iihin}^ was left open at both ends, to make it easy to ascertain whether 
there was or was not an\ leakage. It was assumed that if any vapour was foimd to 
escape from either end of the conduit there must be some leakajfe which would permit 
the water to vaporise. The conduit was allowed to dry thoroughly, which took about 
two weeks; but no vapour has at any time been visible, and th(; loss of heat, which has 
been measured, throuj^h the concrete is so small as to be nej^liji^ible. 

Steel-Cutting Edges for Concrete Caissons. Reinforced concrete caissons sunk 
throui^h rock foi ni the foundation for the main part of the Tennessee River dam at 
Hales Bar, Tenn. There are 26 caissons in all, in sizes from 30 by 32 ft. to 54 by 70 ft. ; 
in sinkinii them there 
was opportunity for try- 
ing;' variations in design. 
Several types of cut- 
tin^-edi^e were tried, 
sketched herewith. It 
is stated by the enf^i- 
neers in chari:je of the 
contract work that the 
last one sketched, the 
round cutting-edge, proved greatly superior to the others; this, of course, applies to 
zvork i)i rock only. 

The rock under the cutting-edge was removed mainly by blasting. An important 
matter was to clear the rock away well outside the outer line of the caisson, as other- 
wise a projecting point might hang up the caisson. The round-edge style of cutting-edge 
was the best adapted to this requirement, whereas the flat-bottom styles, especially the 
first one (6-in. channel base), gave considerable trouble in clearing. 

Blasting with light charges was done close to and right under the cutting-edge 
in all the caissons, but in no case damaged the cutting-edge. The explosive was 60 per 
cent, dynamite. — Engineering News. 

Harbour Work in Belgium. — As a first step towards improving the port of 
Nieuport, at the mouth of the Yser, the only natural port on the Belgian littoral, works 
involving an estimated expenditure of i,7oo,ooof., are shortly to be undertaken. 

According to the plans the existing floating basin is to be lengthened and improved 
by the construction of reinforced concrete landing-stages, and a second head towards the 
sea at the lock giving access to the floating basin will form a chamber-lock permitting 
vessels to enter or leave at all stages of the tide. A diversion of the old western branch 
of the Prunes Canal is to be constructed, which will cause the water from the interior, 
now flowing into the harbour through five locks, to flow directly into the sea. Improve- 
ments are also to be carried out in the roadstead of the port. 

The Department of Public Works has decided to undertake the construction of a 
sea dam betw^een Knocke and Duinbergen for a length of 2,009m. Including the 
necessary staircases (28 in number) to give access to the sea, the cost will be about 
7oo,ooof. The work is to be completed within 26 months. — Times. 

Self-Supporting Concrete Towers. — Two self-supporting concrete towers with 
90 ft. booms are being used to distribute mixed concrete for an eight-storey, basement, 
and sub-basement reinforced concrete building now being erected at St. Paul, Minn. 
The building is 100 ft. by 288 ft. in plan, w-ith the mushroom type of reinforcing, and 
requires 15,000 cubic yards of concrete. As permission from adjoining property owners 
to attach guy wires to their buildings could not be obtained, the towers had to be built 
with sufficient stability to stand alone. 

Next to the building an ordinary tower, made of heavier timber than usual, w^as 
erected. In the rear an auxiliary tower, 10 ft. by 16 ft. in plan, was built to a height 
of about 70 ft. The main tower will, at the time the building is completed, reach about 
175 ft. above the pavement. To counterbalance the weight of the boom and three shutes, 
which are suspended by cables, the rear tower is weighted with stone, its own weight 
not being sufficient to serve as an anchorage. Within the rear shaft is an elevator skip 
on which loaded wagons are driven and materials dumped. After the team is driven 
off the material is hoisted and automatically dumped into elevated bins at one side of 

73 



MEMORANDA. ICQNCBETEJ 

the auxiliary tower. A rectangular timber frame, slidin<4 on the two front timbers of 
the main tower as i^uides, carries the boom and shutes on a pivoted connection. To 
raise the frame a block and tackle is fastened to an overhanging timber extending from 
the main tower, a lead running therefrom to the hoisting engine. The circle of these 
booms is sufficient with the small pivoted shutes at the ends of the main shutes to cover 
the whole area, and a hopper, carried in a sling in the main shaft, is raised or lowered 
to a ])oint opposite any one of the three shutes. Two mixers are placed directly under 
the material bins at the level of the second bend of the main tower, so that it is unneces- 
sary for the elevator buckets to be lowered quite to the street level. 

Reinforced Concrete Water-tank of 600,000 gallons Capacity.— A. reinforced 
concrete water-tank and tower have recently be^n constructed at BerHn, Ont., Canada. 
The tank has a capacity of 600,000 gallo'ns when the water-line is 2 ft. below the top. 
It is 50 ft. in diameter, 40 ft. high, and is formed of a circular shell 12 in. thick at the 
bottom and 8 in. at the top, standing on a reinforced concrete tower 81 ft. high from 
the footings of the foundation. The tank is covered with a fiat-arched dome of 
reinforced concrete 4 in. thick, and the bottom is made up of two domes which run 
into each other, the outer one being inverted, with its low part resting on the support- 
ing tower, from which point springs the inner dome, which is convex to the inside of 
the tank. The bottom is well reinforced to prevent bulging. The inner and outer 
domes of the bottom are so proportioned that the thrusts nearly balance. The thrust 
at the junction of the bottom and the shell of the tank, due to the weight of the shell 
and its roof, is provided for by a large amount of steel reinforcement. The tank 
reinforcement consists of § in. and j' in. square bars of high carbon steel, placed in 
two separate layers where the spacing was less than 4 in. In the inner dome of the 
bottom there are ^-in. rods spaced from 6 in. to S in. apart, centre to centre. Concrete, 
mixed in the proportion of i : i : 2, was used in all portions of the tank in contact 
with water, whereas the proportion in all other places was 1:2: 4. As a means of 
waterproofing the tank, three coats of mortar, gauge i of cement to i of sand, and laid 
on \ in. thick, were u?,ed.—Enginecrino Record. 

ERRATA. 

The writer of the article on " London's Reinforced Concrete Regulations " points 
out that in the first part of the article published in our issue for August there is an error 
in calculating the deficction of a steel beam. It should be : — 

4S LU00X/^4S 357 

As a consequence of this the references to the limiting deflections on pp. 534 and 
535 require modification. 

Concrete Institute Presidential Address. — In reporting the remarks made by 
Professor Henry Adams (page 847 of our December issue), the words given as air 
slaking should have read " over slalsing.'" 

CATALOGUES RECEIVED. 

Richard Johnson, Clapham <Sc Morris, Ltd.- A new catalogue has recentlv 
been jnibli^hed by the cfMUjjany's reinforcfd Concrete Department. Full descrijitions are 
given, accompanied by illustrations of the Keedon and Johnson Lattice svst(>m, both of 
which are well known to our readers. 1 he book also contains some excellent illustra- 
tions of actual work carried out by the (onip.-inw 

Especial attenticjn must, however, be (Ir.iwii to th.' carefullv c()in|)ile(l and \'erv 
extensivf; tables, which are intended to assist engineers, architects, and others in fixing 
sizes ffjr jjreliminary designs, and enabling them to arrive at the sizes of superstructure 
without difficulty. Messrs. Johnson, Clapham is: Morris desire us to state that they 
are, of course, prepared to suf)pl\ all necessary detailed drawings, and to add further 
details not specified in the tables. ThcN' will gladU forward this book and give all 
furthf-r informatir)n upon application lo tlun) at their ollices, 24 and 2(), L<'\'er Sli-eet, 
Manchester. 

The Standard Steel Co., Ltd. This (ompauN has recentl\' issued a handbook 
of structural steel which will doubtless prove useful lo architects, engineers, buildeis, 
and others. Every attempt has been luade to arrange the tables in such a manner that 
any information needed can be easil\- found withoul having recourse to numerous calcu- 
lations. The booklet (onlains tables for rolh-d steel sections used as beams, broad llange 
beams, rolled steel channels usr-d as beams, steel angles used as beams, steel com|)oun(l 
girders, (tc, etc. There are also useful tables for \ai ious kinds of columns, both 
hollow^ and solid, 'i'he booklrt also conlains tables of \\(ights of different forms of 
steelwork, as also various diagranis and illustrations. ('o|)ies of this handbook can be 
obtained from the compan\ at I heir ofiices in Croydon. 

7+ 



7^ 








•«« 


5 » 




p > ■;«. ; 


= S 






1 


1* 

o .o 


is 




! 


!S 
5 -"^ 








m^ 











CONCRETE 

AND 

COMSTEUCTIONAL ENGlTSEEmNG 



\oluine 1\. No. 2. LONDON, FeBRLAKV, 1914. 

EDITORIAL NOTES. 



LABOUR TROUBLES AND CONCRETE. 

The regrettable differences that have arisen between employers and employed in 
the building- trades must necessarily have serious eflects upon the skilled labour 
market concerned in the erection of buildings. Whilst we fully sympathise with 
the principle of the working man having his trade unions to protect his interests 
and rendering services as a benevolent society, we are afraid that the policy of 
some of the leading agitators is quite suicidal to the interests of the man who 
has learnt a trade, and it is certainly not equitable in the matter of demands 
against the use of free labour. But from the purely selfish point of view, as 
advocates of the use of concrete and reinforced concrete, we see in this new 
struggle between employers and employed great advantages for the development 
of the concrete and cement industries. We have only to remember the quarrel of 
some ten years back as between the Plasterers' Union and the builders, to see 
how detrimental that quarrel was for the plasterers and what an excellent thing 
it was for the concrete industries, for it is from that date that we have had the 
enormous development of the concrete slab and the concrete block for partition 
purposes and many other building requirements, which were formerly catered 
for by the skilled plasterer. 

The new strike will simply lead to a greater use of concrete for footings, 
walls, floors, hearths, lintols and roofing, and the bricklayer, the joiner, the 
mason, the slater and the tiler must be materially affected. 

This is regrettable for these particular trades, for they contain some of 
the very best elements of the British artisan class ; but, to repeat, the concrete 
industries must gain, and unskilled labour in particular will naturally reap a 
large benefit, for concrete work employs vast numbers of unskilled labourers, 
excepting in certain forms of reinforced concrete. These men need have but 
little experience, and concrete mixing is one of the simplest forms of labour open 
to all unemployed. 

It has often been commented upon what enormous strides concrete has 
made, both in the United States and in Canada, and economy is generally given 
as the reason ; this is true up to a point, and it is certainly true in respect of 
larger buildings, but in small buildings it does not necessarily always happen 
to be the case, and the great advantage accruing to the employer who is free 
from the trammels of trade unionism has played no small part. Thus, whilst 
the large majority may think the coming strike a great evil for the building 

« 75 



RESEARCH WORK AND CONCRETE. [CQNCBETEJ 

trade, we see in it a future for more economic buildini^-s and less labour troubles, 
combined with the g-reater possibility of using- unskilled labour to get up a 
building rapidly. 

RESEARCH WORK AND CONCRETE. 

In our Memoranda we announce the formation of a British Section of the Inter- 
national Association for Testing Materials, and we congratulate the promoters, 
and particularly Professor Unwin, Mr. Leslie Robertson and Mr. Lloyd for their 
successful efforts in this direction. 

We trust the British Section is the forerunner of a British Association for 
Testing Materials, similar to that excellent institution which exists in the United 
States, and similar to other institutions that exist on the Continent. It is regret- 
table indeed that we should, up to the present, not have had any -real centre for 
research work affecting" constructional materials, and whilst other nations have 
long had their sections or individual associations, and have been doing good and 
continuous work enquiring into matters of the utmost importance, we have 
practically marked time. 

Some work has, of course, been done at the National Physical Laboratory, 
mainly at the instance of certain institutions, and notably lately at the sugges- 
tion of the Institution of Civil Engineers on the matter of reinforced concrete. 
For consecutive effort in research on constructional materials, we have, in this 
country, really only the British Fire Prevention Committee, with its somewhat 
limited scope in relation to materials affording fire protection. 

With the British Section of the International Association for Testing 
Materials, duly formed — and, we trust, a National ^Association in embryo — we 
hope the necessary funds may be collected to enable research work to be done, 
so that we may not continue to take a back seat in the comity of nations in 
this particular department of investigation. The subject is all-important for 
concrete, reinforced concrete, and particularly cement, all relatively new 
subjects, and a vast amount of experimental work is needed. This work should 
be carried out on practical lines, rather than on the ultra scientific lines all too 
frequently met with on the Continent. We again repeat that we welcome the 
formation of this new section. 

OUR CONCRETE COTTAGE COMPETITION. 

We would remind our readers of our announc-emenl regarding a competition for 
concrete cottages, j^artirulars c^f which will be foinid in our adxertisement 
columns, and the full conditions of which can be obtained from the offices of 
this journal, on application to the publisher. 

The subject of our (V)m[)ct ilion appeal's to haxc awakened considerable 
interest, and although to many of our readers, who haxc alread)- attained the 
mf^re successful walks of lilc in ihcir prolcssion, coni|)('tilions cannot ap|)eal, 
we trust they will bring this cjucslion lo tlic nolirc ol ihcii- xoungci' colleagues 
and the members of their si a ft. 



76 



y, CTONXI PlR-nONAI 
AKN(.INH l/IN(, -- 



rill-: HOARD Oi- AGHICULrURE <•- FISHERIES. 




■'ii.^li REINFORCED CONCRETE' IN 

,., fi^i THE NEW OFFICES FOR THE ,^ 

,^^j BOARD OF AGRICULTURE tr 

aS-a AND FISHERIES. j|. 




Although the building here described hjs not 
been constructed of reinforced concrete throughout, 
this material has nei>ertheless played an impor- 



tant part in the 'work. Our article has been prepared for us by Mr. Albert Lakeman, Hon 
Medallist Construction. — ED. 



This new building is Ixjing constructed in W'hilcli.ill I'hicc for ilic accommoda- 
tion of the Board of Agriculture and Fisheries, the various departments of 
whicli are at present scattered \n different buildings in the West Mnd, thus 
rendering the organisation and control more complicated and difficult. The 
work of the Board is very extensive, and has grown considerably during recent 
years, the vaiious additional duties imposed since its establishment in 1889 
including the transfer to the Board of the Ordnance Survey Department, the 
headquarters of which are in Southampton, the jurisdiction of the Ro\ al Botanic 
Gardens, Kew, and the administration of the laws relating to the fisheries of 
England and Wales. The estab- 
lishment f;)r which accommoda- 
tion has to be pro\ided consists 
of a President, a Permanent 
S e c r e t a r y, a Parliamentary 
Secretary, Assistant Secretaries, 
and a staff of administration and 
technical officials. 

The new building is being 
erected under tlie superin- 
tendence of Mr. H. A. Collins, 
A.R.I.B.A., one of the Archi- 
tects of H.M. Office of Works. 
The designs were originally pre- 
pared by the late Mr. H. N. 
flawks, I.S.O. The site adjoins the Hotel Metropole, and is opposite 
the Xew^ War Office, having a frontage of about 150 ft. to Whitehall 
Place, loi ft. to Whitehall Place West, and 136 ft. to Great Scotland 
\ ard. The total height of the building is about 95 ft. from the pavement level, 
and the section illustrated in Fig. 2 is not quite correct, as an additional floor 
has been added by carrying up the roof for another storey. The basement 
floor IS 15 ft. below the pavement level, and in addition a lower ground floor 
is constructed 6 ft. below the same level. The plan of the basement is illustrated 
11^ P^g' 3> 'ind it will be seen that a corner of this is cut ofi" bv the Regent 
Street sewer, which passes under the building at the level shown on the section. 

B 2 

77 




Detail of 
Brackets to 
Columns. 



The New Offices for the Board op Agriculture 
AND Fisheries. 



THE BOARD OF AGRICULTURE & FISHERIES. 



ICQNCRETEl 



This basement, which is to be utihsed for workshops, packing- rooms, and 
stores, is well lij^htcd b}' lar',>-e skylights, which occur at the bottom of the 
two larg-e light wells which are formed in the central part of the building-; 
while the lower g-round floor is directly lighted by windows in the external 
walls, in addition to the interior light wells. The principal entrance to the 




CNTfeANCE 



F'lii- 2. Cross Section. 
TiiK New Oificks for ihk Boatu) ov AoKicii/rnKK and I-'isheries. 

building- is situjited in VVhil( hall iMa(X', and the main staircase and lift arc 
placed in the centre of the ijuilding, with direct light from one of the large 
areas. Reinforced concrete is larg'-ely employed in the construction of the 
building-, and lliis is designed according lo the llennebique system 1)\- Messrs. 
Mouchel and Partners, i>td., of Victoria Street. It is not a C()in|)lclc' reinforced 
concrete huikiing-, howexer, as the external walls are of brickwork, the facades 

78 



li 



fcNdlNKKWlNl. --, 



TIIIi BOARD OF AGRICULTURE <'- FISHERIES. 



hciiii^ laced wilh roilland sloiic; and all iiilcinal walls in which fireplaces 
were re(|iiirr(l wcii- also hiiill ol hrick. i he loads coming on ihcse walls are 
('allied 1)\ blue hi iek i)ieis, and the relainin«4 walls are also ol ihis material. 



Ft 3 







= o 
ft a 



■St 2 



Ihe reinforced concrete work consists of columns, beams, floor and roof 
slabs, and staircases. Trial holes were made on the site to ascertain the nature 
of the soil for foundation purposes, and these showed old brickwork and 

79 



THE BOARD OF AGRICULTURE & FISHERIES. 



[CQNCBETEJ 



concrete, mud, sand and ciay to depths varvino- from 20 to 2=^ ft. below the pave- 
ment level, and below this a layer of gravel was found, varying- from 12 ft. 
to 20 ft. in thickness, overlying the blue clay; whilst water was encountered 
about 27 ft. from tlie surface. A concrete raft was constructed over the whole 
site, this being in two thicknesses, the bottom of which was 6 in. thick and the 




Phoiofirath by lirnesl Milncr. Wandswottli, London, S.W. 

I'lti. 4. li.isement in Course of Conslriiction. 
The Nkw Ofiici.s kor tmk Hcmrd oi Aoricui/iuke and Fishkriks. 

upper lav(,'r i ft. () in. lhi(l<, wilh a conliiuious asj)hah damj) (M)urse belween. 
This asphall was lakcn ihioiigh ihc siirroiiiHliiig wails and carried up on the 
outside I0 form wliat is prad irnIK' a large as])halt tank, in which the 
building is ccjnstructed. f lie raft is covered with paving to form the basement 
floor and the retaining walls, and ()-\n. interior division walls are built directly 
on to the raft uliich loims ihc foundation; while the foundations of the main 
80 



clONyryijc-rioNAi: 



/:t^iV.iS!^li 1 TUB BOARD OF AGRICULTURE c'.; FISHERIES. 



walls aiul columns arc taken down ahoiil ii ft. h in. hclow llic hascnu-nt to the 
layer of i^raxel priw ioiislv mentioned. 

I lie i^cneral (iisj)osit ion and lay-oiil of ilie beams and columns is shown in 




the plan in Fig. 5, Axhich Is a typical floor plan, the reinforced members being 
indicated by the thick black lines. 

The columns are all designed on the Hennebique system, and the largest 
of these in the basement is about 28 in. square. 



THE BOARD OF AGRICULTURE S FISHERIES. 



lOQNCBETEi 




The floors gencrall}' have been 
desii^ned to rariy an external load of 
112 lb. per ft. super, but in some in- 
stances the intended use of the rooms 
is sucli lliat exceptional loads have to 
be carried, and in tliese cases the floors 
were each designed to suit the special 
requirements. 

The roofs generally were designed 
to carr\- an external load of 50 lb. per 
sq. ft. The floor slabs \'aried in thick- 
ness from 5 in. to 6 in. for the ordinary 
cases, and, except in the case of very 
small bays, were reinforced in both 
directions. Typical secondary and 
main beams are illustrated in Fig. 6, 
where the former is 15 in. deep and 

in. wide, witli reinforcement as 
indicated, and brackets 12 in. by 2 in. 
were formed in every possible case 
where the beam is continuous, as 
shown in tlie detail. The main beam 
here illustrated is 19 in. deep and 11 in. 
wide, and it w ill be seen that one end is 
su])j3orted on a wall and the other by a 
column. In ail cases of beams abut- 
ting on cohunns brackets 10 in. by 

1 ft. h in. were formed as shown in 
this t}pical detail. Another typical 
detail illustrating the bracket connec- 
tions between beams and column is 
sh(j\v n in I'ig. i, where the arrange- 
ment of the reinforcement can be 
clearly seen. Reinforced (M)ncrete 
templates were i)r()\ ided under the 
ends ol scxcral reinlorced beams where 
they rested on the walls. 'J'he roof 
work- contains some interesting details, 
and the method of arranging the 
sloi)ii)g beams is illustrated in I^'ig. 7. 
li will be seen that the (lei)lh of the 
beam foniiing the abutment at the 
foot is slightly increased to take the 
thrust, and additional reinforcement 
is pro\ ided. 

Ihe shutlcrini'' and i-einror(H'menl 



J, CX3NM PlIlTIONAl. 
A. KNdlNKKWINC, -^. 



THB BOARD OF AGRICULTURE & FISHBRIES. 



in i).)siti()n lor a j^orlion of this roof work is shown in the i)h()lo^^r:ii)hic view 
illustratcil in F/.i;. S. I'lu' coiuTi'to throii^liout was mac'hinc mixed, and two clcr- 
1ri(' lioists wvvv installrd for raisinj^' \hv mixed eoncriMc lo the different h'\els. 

.\Uhoui;li tliere aic no i-xcepi ional constructional features in tliis building', 
it affords a tv|)ical c\aini)Ic of tin- application of reinforced concrc*le, and further 
illustrates the exti-nsixe use of this material in (ioxernment l)uildin<4S ; and this 




Fi'A- 7. Typical Detail showiag Arratif'ement of Roof Beam. 
The New Offices for the Board of Agricultlre and Fisheries. 



should have great influence with private building owners, a great number of 
whom are so conservative that they are still dubious as to the efficiency of 
reinforced concrete, and consequently do not avail themselves of the saving that 
can be made on the initial cost of their buildings by the use of this material. 

The foundations were constructed by Messrs. Holloway Bros. (London), Ltd. , 
of Belvedere Road, S.W., under a separate contract, and the work of the super- 
structure is being executed by Messrs. Higgs and Hill, Ltd., of South Lambeth 
Road, S.W. The aggregate and sand for the concrete were supplied by the 



THE BOARD OF AGRICULTURE & FISHERIES. 



fCONCKETEJ 



Ham River Grit Co., of Ham and Wouldham, and the steel for the reinforcement 
bv the Whitehead Iron and Steel Co., Ltd., of Tredegar. The concrete mixer 
was a Ransome pattern electrically driven mixer, and the cement was supplied 
bv the British Portland Cement Co., Ltd. 




Photonrufih by lirnesl Miliicr, Waiidsxcorlh . I.imdon, S.W. 

Pi«. 8. View sliowint! Reinforced Concrete Roof Slabs. 
Thk Nkw Oi-ficks i'ok thk Hoako oi- Aokiclltukk and Fishkkies. 



84 



^ 



. trjN.vrytK'noKAL 



THI-: BEST RATIO OF STEEL TO CONCRETE- 




1 



WHAT IS THE BEST RATIO 
OF STEEL TO CONCRETE IN 
REINFORCED CONCRETE 
BEAMS & SLABS FROM £ s. d. 
POINT OF VIEW ? 






By ROHINTAN N. FRAM MIRZA. 

B.EnH., A.M.I.C.E., M.I.M.H., Assoc. Royal T. Collene. 

As the question of economy in construction is one th^t is of considerable interest to all 
studying and dealing with reinforced concrete ivork, the folloiving article may pro've useful 
and of assistance to our readers. — ED. 

In the present article equations are given to prove that, in all reinforced concrete 
structures designed to resist tensile stresses, there is only one ratio of reinforcement 
which conduces to the lowest cost in construction. This will, of course, depend upon 
the market values of steel and concrete, remembering that steel is by far the more 
costly material. 

The cost of labour and material will differ in various localities ; thus it is evident 
that the minimum cost of construction may be obtained by the use of varying ratios 
of steel according to the prices in the district. The ratio of steel that gives this 
maximum economy in the total cost of structure is quite different from the ratio of 
steel to concrete which develops the fullest stresses of steel and concrete. This latter 
ratio is often termed wrongly the " economic ratio," which is a most misleading term, 
for designers may easily misinterpret it to understand it as that ratio which gives the 
minimum cost. 

Although it may appear too previous at this stage to ask the reader to glance at 
Chart No. 3 before going into further details, still it will arouse his interest, for that 
chart represents the varying costs of a set of reinforced concrete slabs with reinforce- 
ment varying from nil upwards. The sharp sudden turn at the bottom of the curve 
will bring home the fact at once, how the total cost rapidly rises for any other ratios 
of steel to concrete but for one particular ratio. 

The charts accompanying this article give a rapid method of finding that particular 
and critical value of reinforcement ratio which conduces to the lowest cost. By the 
aid of these diagrams the required values of critical depth (of beam or slab), reinforce- 
ment, etc., can be determined accurately, when the bending moment on the structure 
is known. 

Although the mathematical working out of the deduced equations is somewhat 
complicated, application of the final results and the reading of the charts for designing 
and checking purposes will be fouad to be extremely simple. 

Let s denote the price of steel per lb. in pence, q denote the price of concrete per 
cu. in. in pence, and G the price of centering per sq. in. in pence. 

All these figures should include the cost of labour, fixing, etc., on the site. These 
values are generally in pounds or shillings per cu. ft. or sq. yd. ; but they can be easily 
converted. Further, the money unit need not be necessarily in pence ; it may be in 
shillings, dollars or any unit, but it must be the same unit for s, q and G. 

The basis upon which the calculations are made is the theory set forward in the 
Report of the Joint Committee (Royal Institution of British Architects) on Reinforced 
Concrete. The same nomenclature is here used, thus: — g- 



ROHIXTAX N. FRAM MIRZA 



ICDNCBETE] 



h denotes the width in inches. 

d denotes ihe effective depth in inches. 

Es 
m denotes the the ratio of the moduli of elasticity of steel and concrete (which 

is generally taken as 15). 
M denotes the Bending Moment at the section considered in in. -lb. units. 
t denotes the tensile stress in metal per sq. in. 
c denotes the con-ipressi\e stress in concrete per sq. in. 
z denotes the distance of resultant thrust in concrete from compressed surface of 

beam in inches. 
kd denotes the distance of neutral axis from compressed surface in inches. 
Ac=khd denotes area of concrete in -compression in sq. ins. 
At denotes the area of metal in tension in sq. ins. 

^^'jj~^' ^^^ ^^^^° °f section of metal to section of concrete, i.e., the ratio of 

reinforcement. 

P=100 p or the percentage of reinforcement. 

/ denotes the span in inches. 

w denotes the load per in. run of span. 

\V denotes the load in lb. per sq. in. 

On page 521 of the foregoing Report, when dealing with beams of rectangular 
ection with single reinforcement, it is stated that—" In a homogeneous beam the 
tresses are proportional to the distances from the neutral axis. In a discrete beam, 
uch as a beam of concrete and steel, on account of the greater rigidity of steel, at a 
iven distance from the neutral axis, the stress in the steel will be ni times as great as in 
oncrete." The formula for the position of the neutral axis s is then worked out to — 

k = \'{p'm' + 2 pm) —pin 
hat is, the neutral axis is lower as the amount of reinforcement is greater, and passes 
lie half depth for 2 per cent. The distance of the resultant thrust from the compressed 
urface is ::=^-^^kd, and bending moment equation becomes — 

M = h A^c (d-hlid) 
= 1 kbd'c (1-U) 

It will be nrjted, therefore, that the strength of a rectangular beam of reinforced 
oncrete can be put directly into the form M = Cbd\ where C has a value which depends 
pon the ratio of reinforcement adopted in the design, taking of course, into consideration 
le maximum stresses allowed, i.e., in concrete and steel. In ordinary design, the usual 
ractice appears to be 600 lb. per sq. in. for concrete in compression, and 17,000 lb. 
er sq. in. for steel in tension. 

I'or the sake of convenience with regard to further calculations, a simple ecjuation 
, needed connecting C and p directly. The etjuation which the author has himself 

educed, C = ,_ (\vh(;re /-» stands for th(; perc(;ntage of reinforcement) satisfies the 

Dndilif>ns and differs at most by 1 or r5 percent, from Hk; accurate values obtained 
y working owX the foregoing equations for C and A', and K and p. 

Allowing (;ne inch of concrete as fire protection below the ix.'ani or slab, tlu; volmne 
concrete used for this piirj) .>se would be //; en. ins., tlier(;f()r(; the total xolnme of 
mcrete used would be dhd'\-lh) cu. ins. 

VohniK; oi st(M:l used = /hd 

100 

Let/= weight of steel p-r en. in., then the weight of steel used = ■^^'"^^' lb 

100 
86 



(a, coNyrvurnoNAn 



THH niiST RATIO OF STEEL TO CONCRETE. 



The necessary ainoiiiit of sluitlerin^,' or centering re(|nired for llie structnre will be 
/ [2(/-i /;J, and the total cost of tlu^ structure, wiiether it he a beam or a slab will be 

Ih</<1 -f Hui +-^''|'jjj^' H-67 (2J 1- /;) units (l) 

The tcUal bending moment on a beam or a slab will be ecjual to that due to the 

imposed loading plus the bending moment induced b}- its own weight. Taking the 

weight of reinforced concrete as 150 lb. 

per cu. ft., the w(dght of the beam or 

slab will be ecjual to '0HC)5n)(l lb. If 

therefore, \V is the load per s(|. in., 

the total bending nioment becomes — 

jy,_Wlbxi o-0865ll)dyi . „ 
^ ^~+ ^ '"• l^^- 

Where 'A may be equal to 8, 12, etc., 
according as to whether the beam is 
freely or rigidly supported. 
117- 




Let -^ 



be denoted by a and 



bv /3. 



0'0865/- 

It has been seen (page 86) that 
.1/ = Clnf 
:.Cbd'' = ab + lidb 
and by the ordinary solution for quad- 
ratic equations — - 

2C ^ C 4C' 
If an actual example is worked 
out, it will be found that the term 

—, becomes negligible, hence 



20 C 2C 



(2) 



It has been shown that a ciirect 
relationship between C and P may be 

NP 



put in the form C = 



P+m 



where X = 



FiGJ l/ennca/ Sca/e. I Cejnfiinefr^ jf 'O 
nomonla/Sea/e / Centime/re = 7.C Oriifs 

cctbu 40 suttbe \o'xio' XooA^ 0.6© Ibs/t)', »*^ ^ '^/a" 



162 and /;i = '5, therefore P= "'^ 

N-C' 
Substituting these values for d and 
P in equation (1) the following value is 
obtained : 

Total cost = lbq 

■'^+2N "CI , „ ,jnflbs 
200 



r^+2^^l^jj^^fnfibs ry:2^n 

L 2C J ^ 200 L ,V-c J 



GI 



[ 



S+ 2\^aC 

c 



+b 



] 



(3) 



The total cost could have been put as a function of d. but by making it a function 
of C matters are much simplified. To find out at what value of C the total cost is a 
minimum, it is necessary to differentiate equation (3) with respect to C, but it can be 
shown graphically that there is a minimum bv plotting the cur\ es as shown in Fig 1 

87 



ROHINTAN N. FRAM MIRZA. [CQNCBEJE] 

Representing total cost by the symbol T^ and differentiating with respect to C 

' 200 L Vc{N-cY J ' L c- -I 

To determine that valne of C which will make Tc a minimum, it is necessary to 

i^\ ^ A ^ ( n M^ ; . cost of steel per lb. , 

equate equation (4) to zero and solve tor (. It i.e. — ,; 7, L)e 

^ ^ q cost of concrete per cu. ft. 

denoted bv symbol R, and — be denoted by 7, this minimum yalue is given by 

' ' _ ^^ 

_ /i^+ y/aC , iTifR 

C ^ 100 



^+\/ 



c 



V N y/a+ v^C (3+ y/«C) 1 ^ ^ [ _ /^+ v/^Cl ^n (5) 

L Vc[N-cY -J ^ <^' -I 
100 L sci^-cy J 



(6) 



The above equation is fairly complicated owing to the presence of i^. Now from 
various examples it has been found that by neglecting /^ in the above equation, it reduces 
the deduced value of C by very nearly 4 per cent. Hence to avoid unnecessary 
complexity it is better to neglect /^ temporarily and then adjust the equation afterwards 

It has been stated before that /3 = — -- — and is also equal ^ol — 7^ U. 

Temporarily neglecting /^ equation (6) becomes 

1 . mj R i N + C ) _ .^) 

C ioori + 7) ^{N-Cf\ 

T , 100 . R _r. 

Let -=;/ and , = Rx 

mf 1 + 7 



Solving the quadratic for C 



U 7^', + 8/^,;i + /^, + 2^f) ' 



This equation shows that the va'ue of C and hence the ratio of Reinforcement 
which makes Tc a minimum is dependent upon the ratio of s to q—i.e., the price of steel 
to concrete. 

It can be shown that the error involved in evolving the value P by neglecting jRf' 
(under the srjuare root sign) is so small, as compared to the exact value from equation 
(8) as it stands, that for practical purposes it is justifiable to neglect A^,' which reduces 
equation (8) to a simple formula. 

I'urther (-i has been temporarily neglected. To adjust for its loss, equation (8) 
should be multiplied by r04. This increases the value of C to the necessary amount. 

Thus neglecting A',' 

2A^;fXl-04 _ 

~ \2v'2R^ + Ri-]-2n] 

2NnXV04 .... 

or C = ; — } ; — /— ,., v ' 

iv Ri+V2ny 

Substituting in the above e(iuation the vahujs of A*, and n 

200WX1;04 , (,„, 

,,,/rv «-+V2""'i 

L 1-1-7 mf-' 



88 



K'tSr.iNKll^'^'^1 ^^^ /i/iSr RATIO OF STEEL TO CONCRETE, 

This is the general (Mju.'ition of the economic C in terms of s\mboIs. Giving (he 
constants .V, /// and / their respective vahies U)5, '5 and "29 (assuming that steel weighs 
f )() 11). per cube ft.) 

232900 (11) 



C = 



[^r^ ''-^y 



IG 

where 7 = ~r ' 
qb 

This ecjuation applies to both beams and slabs. In the case of slabs b is a very 

arge quantitv, as compared to the depth, and the expression ~ becomes exceedinglv 

small compared even to unity, and could be neglected ; therefore for slabs, formula given 
by equation (II) can bj still further simplified by dropping out 7 and the expression 
becomes 

^^232900 (12) 

(\ R ziiy 

This equation can be put in. any convenient form ; thus if s were price of steel per 
lb. and O price of concrete per cub. ft., then calling S Q=J, R in the above equation is 
equal to 12' xj, and by substitution another formula can be evolved of the form 

V 

V^R + B- 

The truth of the above equations for C can be conclusively proved by working out 
arithmetically an actual example and by plotting various values of total cost with 
corresponding values of C, to show that there does exist a minimum value of total cost. 

Example I. 

To take an actual example such as the following case of floor panels in a large 
building, let s, price of steel = Id. per lb., price of concrete = Is. per cube ft., and 
price of centering = 27d. per sq. yd. For slabs, there will be little or no centering 
required along its depth, the chas3 in the walls acting same. In this case only the 
centering for the superficial area will be considered. 



c=r /^ — T n3) 

La/p-urJ 



Total cost =lbq , _l7;,^_l x — ;^- ^— ^ -fr^/'^O-l-/)] 

'' 20 (^''^^^ 200 [162-C] ^^^^^^^^J' 

w = 288 lb. per sq. f t. = 2 lb. per sq. in. 
/ = 120 in. 
6 = 120 in., and number of panels in the building be equal to 40. 

Taking ^=12 a = -1^ = 2400. 

r 
/^+2\ ^=100(1+ \"C) very nearly. 
Cost of concrete for 40 panels in £s. 

_ 120x 120X100(1+ \'C) 40 
144X2XC 240 

-i:833[l^]. 

Cost of steel for 40 panels in ;^s. 

^•29X120X120X'5 XIOO (1+A^O 40 
200xi2x(l62-d ^20 

Vi62-C/ 



89 



ROHINTAN N. FRAM MIRZA. 



^rjNCia^im 



Fireproof one-inch concrete covering cost = ;^s 16'666. Cost of centerirg for 
40 panels @ 27d. per sq. yd. = ;^50'000. The total costs corresponding with various 
values of C have been plotted in Fig. 1, and are also given in the following table : — 



Percentage of 
Reinforcement. 



0*224 



0625 



0'69 



c 

1+v/C 

l + y/C 

C 
162-C 

833(HVC) 

174f l+s/c \ 

)2-cy 






1 

ex 

162 
£ 

oc 



50 

7-071 

8-071 

0-161 



90 

9-487 
10-487 



94 

9-695 
10695 



0117 0114 



112 

134 



72 

£ 



68 
£ 



97-46 950 



1-04 1253 2523 27-14 



\162 

Centering Cost 500 500 50-0 

Fireproof Cost 16-66 16*66 16*66 

Total Cost CO 213-19 189-35 



50-0 
16'65 



0'73 


0'81 


1*04 


4-0 


96 


100 


110 


144 


9-79 


100 


105 


12*0 


10-79 


11*0 


11*5 


130 


0112 


Olio 


0*105 


0-090 


66 


62 


52. 


18 


£ 


£ 


£ 


£ 


93-5 


91-63 


87*5 


75-0 


28-53 


30*97 


38-45 


125-63 


; 50-0 


500 


50-0 


50-0 


1 16*66 


16*66 


1666 


1666 


188-69 


189*26 


192*61 


267-29 



CO 



162 
12-72 
13-72 

0-085 



£ 

71-0 



00 

50-0 
16*66 

00 



Fig. 1 shows that the Tc has a minimum value somewhere between C = 94and 
C = 96. 

Instead of laboriously working out this table every time, the economic C can be 
very quickly worked out from equation (12). 

/? = -= 144 in this particular example, substituting this value for R in equation 
Q 

^ ^ 232900 



and 



C = 96 (by slide rule) 

P= "^^^ = 72 
162-C 



This value of C agrees very closely to that given by plotting Fig. 1. 

Example II. 
Taking the same values for steel and concrete as given in Example I., and assuming 
that price of centering per sq. yd. is 27d., to find the economic C for a beam whose 
breadth is 12 in. In this case 

232900 

c=- 



(V ^L +37-l)^' 



R=\AA 



L9 /. 144 J 



V 



144 
/. =*5 
12 



li 



= 9798 



7 



C= 108; therefore P=VQ>. 
By using the proper value of C the most economical designs can be produced, and 
a considerable amount of money can be saved. Undoubtedly cases may arise where the 
designer will have to choose other values of C for the sake of gaining advantages in some 
other direction, such as head-room, floor cut through by openings, etc., but in the author's 
experience he has fmind that the use of this formula saves much time in the office and 
yields very satisfactory results in practice. 



90 



CTON.vrUUCTIONAi: 



THE ni^:ST RATIO OF STHEL TO CONCRETE. 































Fir 


?. 
















































































1 
























c 


-- ^ 






















q 


-Cc'ST 0» CoMCRr Tl PtM 1 

Cubic Inch ^ 
C » 3oo L»» f\.i» S9o««t 


» 


















( 






















Inck 






















t • /7noo 












































































































-life 




























































































-Ho— 


\ 






























-loo 
-9o - 


\ 


\, 




























>l 


\ 




























-80- 








^°< 


^->, 






















7o - 


U 










V^ 


^ 


-C^r 
















Joo- 

So 



















^^ 


ifjK. 












-I 
< 
> 






























































-3o 
































-2o 










































1 
















U^] 


^ 




too 

1 


1 
2oo 


l/.L.U or R ' 
300 AOO 

1 1 


Soo 


Goo 

J 


Zoo 


8c: 



^/6 2 Vcytical Sca/e I Cof^ti/riefrc • 10 Units 
m '•tLCti/o/ Sca/t / CenfimeJi-e • 6oUnifs 



NP 

P+ 



J' 



'11 1 is v.'iluc of C to },'ive 
a inininimn cost can be 
obtained from a curve con- 
necting' R and C {lu^^. 2), 
and knowing C, the vahK; of 
P i.e. the percentage of 
reinforcement— can at once 
be obtained from the 
ecjnation 

162-C 
or by referring to the chart 
given on paj^e 536," R.I.B.A. 
Report on Reinforced Con- 
crete, No. I.," or the curve 
given in F//f. 4. 

A General Review. 

An examination of the 
cost curve {Fig. 1) will show 
that the total cost rises much 
more rapidly for values 
above the critical value of 
C than for values below it, 
and this unduly increases 
the cost of steel. 

A stress of 600 pounds 
per square inch has been 
assumed as the working 
value for the stress (com- 
pression) in concrete, but if 
another value be chosen, 
say 750 pounds per square 
inch, an equation connecting 
C and P would be obtained 
of th ■ same form as before, 
but with slightly different, 
values for the constants as 
follows: — 



JU 



where c=compressive stress (working in concrete psr square inch). 

A'=ratio of the distance of the neutral axis from compressed surface to the 
total effective depth d. 

c has been taken as equal to 600 lbs. per square inch, therefore 

/v[l-Hv]=|q^ (14) 

Changing the value of c for a higher value of 750 lb. per square inch in com- 
pression. 

c .. , , . 750 •54P 202*5P 



C = '^K{1 



--,,._750 _ 



(15) 
91 



RO HI NT AN N. FRAM MIRZA. 



[CQNQgETEi 



Similar changes will require to be made in the value of .V in equation (10). 
If wrought iron were used instead of steel,/ which stands for the weight of material 
per cubic inch will have a different value in equation (10). 

A few words should be said with regard to the deduction of equation C = ^~t^ 

which has been used 
throughout for deducing 
various equations. This 
equation traces the rela- 
tionship between C and 
P, so that the compres- 
sive value for C, that is 
600 lbs. per square inch, 
may not be exceeded. 
The exact fundamental 
equations indirectly con- 
necting C and P are 

C=|x(l-iX)andX= 

V {p-'m' + 2pm) -pm, 
remembering that P is 
the percentage of rein- 
forcement, while ^ is the 
ratio of reinforcement, 

i.e. p= • 

^ 100 

If these fundamental 
equations were to be used 
in the total cost equation 
for deducing the eco- 
nomic C by differentiat- 
ing, the mathematical 
working out and the 
results will be so complex 
as to be of little or no 
use in actual pra.ctice. 

While admitting that 
a certain amount of 
approximating has been 
done, it must be remem- 
bered that it has been 
done with great care, so 
that the final result is 
not affected. 

The equation of the tr)tal cost can be represented in terms of the depth of the slab 
or the beam. Probably it is easier to do so than to represent it in terms of C, but while 
differentiating to find the solution of the most economic d, it was found that the problem 
became somewhat complex, and making the total cost a function of C helped to simplify 
the conditions. 

































Pi^ 


^. 












































































































































































A 






































































































to 
































2— 

•- 


































O 




























■^ 






-3So 
























-r^ 


y 








-ibc 

-ato 






















^-f 


^ 


























T> 


.°>^ 
s-^^ 














~i»y 
















.^^r 


y 
















-27o 
-250- 

■Viio 

\ 

I70 
-lio 












\ 


f 


^ 


























0°^ 


^ 


























^^^ 


^^ 


"^ — 


























^ 


\ — 


























'w ^ 




























































































































































^ v^ 


-So- 
-To 































-(^ 


/; 




1 




. f " 


3 


09 R 


tiNFORCtfvtt.' 

'^ 1 


1 




G 

1 




7 




? 


IV 


VvS C 


U/lVi 


/ 


iorizo 
bo 


4,ca/ 
rita/S 


Sca/e 
ca/e 


/ Cer 


nflmd 


ne - 
e ' 


S Ur, 

a. c 


Vatcx 


a« 


> vn 


S 


T 





92 



y, C"0NyrPUCT10NAi: 



THE niiST RATIO OF STHHL TO CONCRETE. 



In actual practice the value of d can be obtained directly from etjuation (2), i.e., 
^ ~2C r '^ ^'^^ bendinf? moment due to weight of concrete is to be considered, or 

(i= p if this is neglected. 



»5o 



FmS'.^ 



Evolving the value of li in the foregoing example, to give the mininnim total cost, 
100 , aA^^O 
^x^"*" "qr^~^"^"^"^^'^^~^*^"^ inches. It will be noticed that the increment 

in depth due to the bending moment of the weight of concrete is 0"521 inches, and it is 

very advisable to calculate the value of d, which includes this value. 

'50 
When C=96 7^=72 from the equation, P=.^^_^, aiud from the table on page 90 

a curve can be drawn showing how the total cost varies with P (Fifi. 3). This curve 

will show the percentage of 

reinforcement beyond which it 
is advisable not to go, except 
at the sacrifice of considerable 
expenditure. The curve gives 
the costs both at 1*7 per cent, 
of reinforcement and 0*25 per 
cent, as ;^210, the minimum 
cost being, as before, seen 
from the curve £l88'6 at 72 
per cent. 

In conclusion it may be 
useful to summarise the various 
results here : — 

(l.) There is only one 
value of the ratio of reinforce- 
ment which gives the total cost 
of reinforced concrete slabs as 
a minimum, and this total cost 
depends on the cost of steel 
and concrete, including labour, 
fixing, etc., on the actual site. 

(2.) It is not always econo- 
mical to develop the full 
stresses of steel and concrete, 
for although it may give a 
higher mechanical efficiency it 
may be at a considerable 
increase in cost, which is not 
always acceptable. 

(3.) Similarly there is one 
definite ratio of reinforcement 
which gives the cost of rein- 
forced concrete beams as a minimum cost. This value depends on the price of steel, 
concrete and centering, including labour, fixing, sawing, etc. 

(4.) The value of economical ratio of reinforcement for beams is higher than that 
C2 93 




o-OOS oo\o oo\5 



o-Qru> 






ROHINTAN N. FRAM MIRZA. 



ICQNCBETFJ 



for slabs, on the assumption that in slabs very little centering or none is required for 
its depth, while in case of a beam, the centering' required along its depth is an important 
item. If a special case of slabs arises which require considerable centering with refer- 
ence to its depth, then such slabs should be treated as beams. 

(5.) If a high price for steel has to be paid, it is better to buy the material having 
a high tensile strength, for if on a job the steel cost is likely to be 2 id. per lb. owing to the 
use of special bars, and concrete cost were to be Is. per cube foot, then from equation 
(12) C=74. hence/) = *0045, which means that /v=*31, and from the fundamental equation 

mc A' 

f — 1 _ 7- (and as C is COO lb. per square inch for concrete in compression), t the 

tensile strength for steel per square inch will be 20,000. 

(6.) Special cases may arise with reference to this subject, and many correspondirg 
formulae may be evolved with little effort from the primary equations. The main object 
of the mathematical investigation is lo suggest a method by which other problems of the 
same nature may be tackled. For example, the fundamental equations assum.ed here are 
nic K 
f —Y—j{ ^"^ 1 - cbKd=pbdt (see No. 1 R.I.B.A. report, page 521), but some other 

authorities adopt the following, assuming that the stress strain curve of concrete is a 
parabola and not a straight Ime : ~f^Y^K ^^^ ^^^ chKd=ph.dt. 



/' 



This means t hat in the first case A'= '^^W+2 pm-pm, while in the latter case, 

This will naturally mean a slight alteration in the 

•547^ 162 P 

p_|_-5 or ^— p 1 .5 and finally in equations (11) and 



h'='75y^ p')ii- ^2.66 pni—pm 
deduced equations A' 1 — 3 A' 
(12), but the difference will not be very serious. 



94 



/ J, t"ON.vri.'IK"IIONAl-l 



REINFORCrin CONCRETE IN SAN FRANCISCO. 




REINFORCED 
CONCRETE IN 
MUNICIPAL ENGINEER- 
ING WORKS IN SAN 
FRANCISCO, U.S.A. 



Fig. 1. Reinforced Concrete I'umpiny; Station, 
San Francisco. 



E. R. MATTHEWS, A.M. In I.e. E. 

F.R.San. Inst., 
Borough Engineer of Bridlington. 



Some interesting examples of municipal 
ivork in reinforced concrete ha've recently 
been carried out in San Francisco, and ive 
are able to gi've a few particulars and illus- 
trations of this ivork in the subjoined article. 
—ED. 



The use during- the past few years of reinforced concrete in the municipal works 
which have been carried out by the City Authorities of San Francisco has been 
\ erv extensive. 

Servers. — This material has been used with marked success in sewer con- 
struction, and in a previous issue of this journal a description and illustration 
of its use for this purpose in the construction of the Minposa outfall sewer were 
g-iven. 

Since that sewer was completed, the City Engineer of San Francisco, 
Mr. M. MacShaughnessy, has put in other sewers in this material, notably the 
Lincoln \\'ay sewer (see Fig. 3), and the Division Street sewer outfall (see 
Fig. 2). The former is a reinforced concrete circular sewer with invert lined 
with brickwork; the latter consists of reinforced walls and floor and roof slabs 
forming three openings, through which the sewage passes. 

The Kentucky Street sewer has also been constructed. This is an egg- 
shaped sewer (except that it has a flat top), and is 2 ft. 6 in. by 3 ft. 9 in. in 
size (see Fig. 4), and is a plain concrete sewer with l)rick invert and reinforced 
concrete slab roof. 

Reservoir Construciion. — The Twin Peaks reservoir, completed about 
eighteen months ago, is one of the finest examples of a reinforced concrete 
reservoir tO' be found. It is oval in plan, and is di\ided into two parts by a 
reinforced concrete dam, for which purpose the material used is admirable. Fig. 
5 shows a portion of the floor of the reservoir, and is a good view of the reinforce- 
ment, showing preciselv the arrangement of same. The completed reservoir as 
now being used is shown in Fig. 7. These photographs illustrate a \ery excellent 



95 



£•. R. MATTHEWS. 



CONCB ETE] 




Fig. 2. View showing Sewer Outfall Construction. 
Reiniorced Concrete Sewer, Division Street, San Francisco. 




I-i»<. 3. Sewer Construction 
Kki.'iIokcf.h Concbktk Skwi k, LiNf;oi.N Wav, San I'"rancisco. 



96 






REINFORCED CONCRETE IN SAN FRANCISCO 



piece of cnj^inccriiij^ work, wliirli rcllccts ^rcat credit on the Cily lui^inccr, 
who (k'sij^iied \hv works :in(l suj)cr\isr(l llu'ir construction. 

A r<w partic iii;irs rci^ardinj^' this inlcrcstinj^- rrscrxoir may l)e usciul to 
tliosc of your rcackrs wlio arc interested in waterworks cng'inccrin^. 

'I'he rescrxoir is 750 ft. ahoxe the business section of San I'lanc^isc^o, and if 
part of tile hii^h pressure system for fire extin^uisliinj^" |)uri)oscs, estai)iished in 
consequence of ihe terril)le fire of 1906. The reservoir is 370 ft. f)y 2H5 ft. 




Fig. 4. View showing Sewer Construction. 
Reinforced Conxrete Sewer, Kentuckv Street, San Francisco. 

in area, and allows for a depth of water of 2'^ ft., or a capacity of 11,000,000 
gallons. 

One half of the reservoir may be filled while the other half is being cleaned 
or repaired, and the buttresses are spaced at 9 ft. centres, and are uniform on 
both sides of the division wall. They are i ft. in thickness and 13 ft. wide at 
the base. 

On the completion of the work one half was filled to a depth of 25 ft. 6 in., 
the other being used as an auditorium in connection with the opening ceremony. 

97 



E. R. MATTHEW'S. 



ICONCKETE] 



Before being- filled, ihe reservoir was washed down with cement by means 
of a cement *' g-un " ; this waterproofino- operation took eight days, and the 
work was executed by the Pacific Cement (iun Co., of San Francisco. 




Fig. 5. View showing Reinforcement. 
Ki.iNiORrED C<jncrkte Rkskrvoir, Twin Peaks Reservoir, San Francisco. 




98 



I IK. G. Vitw of J'tiinpiiiK .Stati(jn in course of ccnstruction, 

RKINIf>IU;KI) CONCRKIK I'l MI'INO SlATION. SaN FrANCISCO. 



A^^S?.S£al^ RI^: IN FORCED CONCRETE IN SAN FRANCISCO. 







99 



E. R. MATTHEWS. 



riant reinforced concrete work 






been erected in the 





i 

^ »! II III III III Ml 



I 



Ik Ilk At ^k 

ipri iRff flHi ilBI 



.^^ 




Pig. 8. View showing Finished StriicUirc. 

REINFORCKD CONCRKTK PfSMMNO StAT.ON. SaN FkANC.SCO. 



and rcprcH-nls some cxrHl.nt ;.n Inf. , u, 



:,1 uork. Fiv;. 6 shows the interior 



and rcprcH-nis sonn . -n ,.,»„mru(Miun /mV. 8 shows 

view of the machinery room m .ouisr ol .onshudum. ^ 



the 



lOO 



l^lNoiNhKRTS^g] RBINFORCED CONCRETE IN SAN FRANCISCO. 



C()ni])li'li'(l slriicliiic, iiK'IiKiinL; tlu' rcinlorccd {-oncrt'lc' rhimncN-. {"i^s. i ancl 9 
s)u>\\ tlu" l)uil(lini4' in course ol iTi'ction. 

'I'lu' MUlIior would, in coiKlusiou, expicss Iiis inrlcljlcdncss to the City 
I^ui^inrc-i- of S;in P'rancisco, Mi-. MacSh.iuj^'-hnc'ssy, for his l<indiu-ss in sending 
hini ihc j)liot()i4raj)hs of llu'si- iinportanl \\()r]<s and for j^ixin^' him llic j)ri\ilege 
ol rc'])roducini;" tlirni. 

lie would slate that, in his oj)inion, reinforced concix'le is ihe best material 
to use in reserxoir and cuherl construction in {his country, as well as in 
countries subject to earthquake shocks. 




Fig. 9. Building in course of construction. 
Reinforced Concrete Pumping Station, San Francisco. 



TOI 



THE IXSTITUTIOS OF CIVIL ENGINEERS. 



ICdNCBETEl 



UMKUU 




THE INSTITUTION OF CIVIL 
ENGINEERS & REINFORCED 
CONCRETE. 







Second Report of the Committee on Reinforced Concrete. 

In Volume V, of this Journal— October, No^)ember, December, 1910 (pp. 703, 707, 798 ana 
880) — loe dealt 'very fully ivith the Interim Report of the Institution of Ci%>il Engineers 
regarding Reinforced Concrete, The Second Report has noiv been issued, and although 
someiv'jst disapDOinting as a ivhole, such points as are of interest in the report and ivhich 
call for attention are dealt ivith in this article, the first part of Tvhich appeared in our 
December issue. Giving to lack of space this article had to be omitted from oar January 
issue, — ED. 

CALCULATIONS FOR REINFORCED CONCRETE. 

The calculations for reinforced concrete are dealt with in Memorandum F, and the 
statement was prepared by Mr. F. E. Wentworth-Sheilds and Professor J. D. Cormack, 
D.Sc, and generally speaking we find that it is somewhat disappointing. The notes are 
incomplete and appear to be a repetition of portions of the Second Report of the Joint 
Committee of the Royal Institute of British Architects, whereas we should have looked 
for more originality in an Institution which refused to co-operate with other Societies, 
and certainlv there is a lack of completeness and authority which is surprising when 
the status of the Institution is considered. The usual assumptions were made in 
deriving the formulae, and these were as follows : — 

(i) The stresses in both steel and concrete are proportional to the strains (straight- 
line theory). In other words, the moduli of elasticity are constant for both 
steel and concrete, and hence the ratio of the moduli is const.ant. 
(2j A plane cross section remains plane after loading. In a piece subjected to 
bending this means that the strains in both concrete and steel are proportional 
to the distance from the neutral axis, and hence from assumption (i) — the 
stresses in l^oth concrete and steel are projjorlional to the distance from the 
neutral axis. 

(3) The tensile strength of the concrete is considered to be zero. 

(4) 'Ihe stress in a reinforcing bar of small section is considered as uniform over 

the whole section. 
In addition, it is usual when designing to assume that : 

(5) The initial stresses set up in concrete and steel owing to changes in volume of 

concrete while setting are zei'o. 

{()) 'Ihe stresses set up in concret(; and steel owing to changes of teni])erature are 
zero, |>r(n'id((l the whole j)iec(' is free to expand or contract. 

The ("omiiiittee ,'ipj>ear to l);i\'e l.'ikcn a great deal of Irouhlc in tr\ing to pro\'e that 
these assumptions arc not strictly true in .ill cases, and \( 1 tli<y adopt I hem and have 
no suggestions or recommendations to offer which aic the outcome of their lindings. In 
dealing with the value of lis/ Id the siatenieiit is m.ide th.it this \ ai ies from 10 to 15, 
but as a matter of f;icl it will be found to \ary e\iii more iIkhi this, and no mention is 
mad(; of the influence cjf the r<inforcement such as we lind in ihe Report of the 1^'rench 
Commission dii CinienI Anne, where it is staled that it is preferable to regard the 
co-efficient as the result of experience on pieces with longitudinal and tiansverse rein- 
forcement, and not as re|)resenting the ratios found from concrete and steel separately. 



102 



X'Soi™?iRg^'] report on reinforced concrete. 



The results of lists on rciiiforccil hcains as ohsciNcd arc such ihal llicv aj^rcc with the 
position of the neutral axis as found by usinj^ the value of Its / Ec= iz,, but there is a 
certain vai^utMiess in tlu- manner in which tile notes of the Committee are jjresented 
that has the effect of Icaviui^ the icader rather uncertain as to what is really recom- 
mended. It is stated that (he icsuits obtained by assiuiiin^ )}i .1. m are in most cases 
rather safei than if )ii 15 is assumed, althouj^h the majority of countries make the latter 
assumj)tion. We assume that the latter fact accounts for tlie Committee adoj)lin^f a 
value which ai)|)arenlly does not quite coincide with their own deductions. 

b'ollowini; llu' assum|)tions that are ado|)te(l and the reasons for and aj^ainst such 
assumi)tions, ten formula.' are t^iven for beams and columns which are stated and 
obtained in the Second Rej)ort of the Joint Committee on Reinforced Concrete appointed 
by the Royal Institute of British Architects, and some notes are then j^iven on 
deflection. 

Despite the importance of the subject, we notice that no recommendations are made 
with reference to the values of the bending moments for fixed and continuous beams 
and slabs under different conditions of loading, and there is some difference of oj>inion 
on this question amongst engineers. It must be considered a great oversight on the 
part of the Committee, who appear to commence in the middle of the subject, and 
omit all consideration of those points which are the first to be dealt with in actual 
design. It appears to us that some useful work might have been accomplished in this 
direction, whereas the whole question has been entirely neglected. 

The few general notes that are given in the calculations do not appear to be of 
much value, and the Second Report of the R.I.B.A. has been drawn upon to such an 
extent for the formulae which are stated that very little credit can be given to the 
Committee of the Institution of Civil Engineers. Surely there is still a large field for 
investigation which is open to a committee of this kind, and assuming that thev 
approve of the work already done by other Institutions, this could be endorsed, and 
attention devoted to the consideration of those matters which are at present in a more 
or less unsatisfactory state. There is the question of the frictional stress between 
concrete and steel which has not yet been sufificiently investigated, the bending moments 
for continuous beams, the design of column foundations, the question of eccentric 
loading on columns, and many other items which might with advantage be dealt with 
and investigated thoroughly, with a view to deducing some reliable information which 
would be of value to engineers. 

Following the notes on the calculations are various tables giving in a brief manner 
the results of some experiments made in France, Germany, the United States, and 
Great Britain on columns reinforced in various ways, and comparing the calculated 
safe loads with the actual loads required to cause failure. These results indicate that 
the R.I.B.A, formula is quite satisfactory, and the notes attached and explanation of 
the tests and the results are interesting, and indicate the range of experiments, the 
manner of failure, and the effect of the longitudinal and lateral reinforcements. The 
experiments conducted in Great Britain include those carried out for H.M. Office of 
Works by Messrs. Kirkaldy in 1908-9, and described in our issue for March, 19 10, and 
those carried out by Mr. \V. C, Popplewell at Manchester, 191 1, a copy of this table 
being here given. 

REPORTS ON WORKS EXECUTED. 

The reports on works executed, which are contained in Memorandum " J," cover 
a variety of structures in various countries, and they deal with the nature of the 
structure, the age, external influences, general condition, materials used, and failures 
or deterioration. Many of these reports are quite interesting, and they tend to show 
in which direction failure or deterioration generallv occurs in the actual work, and 
therefore the notes should be of some value to engineers. 

103 



THE INSTJTUTIOX OF CIVIL ENGINEERS. 



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104 



f.^cousvmK'vioNAii REPORT ON RHINFORCIiI) CONCRETE. 

/\. E-N01NKI-R1NC-. -- I 



W'c ha\(' (Ir.'.wn upon the Report by quolin^ sonic of the icporls j^ivcn of work 
cxocutcd abroad. 

W'c <4iv(' Inst two New Zealand rxanipUs ; one a ntainin-^ wall, and the second 
sonic reservoirs and tanks. 

Retaining Wall at Miramar, New Zealand. 
This report is presented b\ Mr. James Marchbanks, M.Inst.C.l^., and reads as 
follows : — 

General Descrifticn. — A wall in reinforced concrete, 1.430 ft. in length, erected on 
the sea coast, partly serving as a retaining wall and partly ais a parapet, with foundation 
at mid-tide level. The work has only recently been completed from the designs of the 
author, and shows signs of vertical expansion cracks. No details of cost are given. 
/. Age. — The wall was built in igio-ii. 

//. External Influences. — As the average rise and fall of the tide is 4 ft., from 
2 to 3 ft. of the foot of the wall is immers^ed at every tide. The whole of the rest is 
exposed to the influence of moist air. 

///. General Condition. — Vertical expansion cracks have aj^peared about midway 
between the buttresses and were found in some cases before the earth had been filled in 
behind the wall. They vary from hair cracks, at the top of the parapet portion, to cracks 
of 1-32 in. in width, becoming narrower down the face; some reaching the thickened toe 
of the wall. The worst of these cracks have been cut out and filled with cement mortar, 
but it is apparent that motion has not yet ceased. 

IV. General Features of the Design. — The wall consists of a thin vertical and 
horizontal slab ioined by triangular buttresses at intervals, the weight of the 
earth filling on the bottom slab ensuring stability. The height from the foundation 
to the top of the filling is 12 ft., and above this there is a parapet 4 ft. high, curved out- 
wards to deflect waves and spray. The buttresses, 9 in. thick, are introduced at intervals 
of 10 ft., and the beam at the heel of the wall has a breadth of 12 in. and a depth over 
all of 21 in. The bottom slab is 10 in. thick and the vertical panelling tapers from 13 in. 
at the bottom to 11 in. at the top. It was presumed that the pressure would be uniform 
throughout the structure, so all the parts were treated as fully continuous. 

V . Materials. — The concrete was mixed in the proportions of 1:2:3, and consisted 
of shingle from the sea beach not containing any stone larger than | in., and unwashed 
clean sea sand. The Portland cement of New Zealand manufacture had to comply with 
the British Standard Specification of June, IQ07. Mild steel with a tensile strength of 
not less than 60,000 lb. per sq. in. was used for the reinforcement. 

VI . Methods of Construction. — The concrete was mixed by hand in small batches and 
transferred direct to the casings. The casing on the seaward side of the wall was con- 
structed to the full height before any concrete was deposited, and that to the landward 
side was carried up in about i8-in. lifts as the concrete was deposited. The casings were 
left in position for a month or six weeks. 

VIII. Failures or Deterioration. — Of the total length of the wall 1,180 ft. is built 
as a monolith in one straight line. It is thought that this is largely responsible for the cracks, 
as they might have been prevented by the provision of suitable expansion-joints. It is 
considered that better work could have been obtained if the base of the wall, situated at 
mid-tide level, had been kept above high water. No tests of the structure were made, 
and the details of design and reinforcement are shown in the accompanying section. 

A Water Tower on North Island, Main Trunk Railway, and a Reinforced Concrete Tank at Mataroa. 

This report is presented by Mr. F. W. Furkert, A.M.Inst.C.E., and reads : — 

General Descriftion of Water Tower. — A structure in reinforced concrete, 70 ft. in 
height, intended to store 10,000 gallons of water, to give effective pressure for washing 
out locomotives. The stand, which is 10 ft. square on top, consists of four legs, each 
tapering from 18 in. square at bottom to 14 in. square at top, tied together by walings and 
knee braces. On the summit is a system of girders supporting a tank 16 ft. in diameter 
and 8 ft. 6 in deep, without a top. It is in excellent condition, free from leaks and with- 
out a crack. The work was executed from the designs of the author at the end of 1908. 
No details of cost are given. 

/. Age. — Erection completed in November, 1908. 

//. External Influences. — Extreme range of temperature 10° F. to 150° F. Tank 
sometimes empty at high summer temperatures, and filled at different levels with ice- 
covered w^ater in winter. Exposed to gales which may reach 40 to 50 miles per hour. 

///. General Condition. — Excellent ; free from cracks and leaks or even a moist spot. 

IV. General Features of the Design. — The legs of the stand carrying the tank are 

IOC 



THE INSTITUTION OF CIVIL ENGINEERS. ICQNCBETE] 



braced by six tiers of walings, and the same number of internal diagonals. The hori- 
zontals between the tops of the legs, in addition to acting as wind braces, had to project 
outwards and serve as cantilevers, outside the lines of stand, so as to support as much 
water beyond the area of the base as within it. The tank itself was designed as a tub, the 
hoops carr\ing all the stress. The whole structure, tank and stand, was designed to 
resist a wind pressure of 50 lb., no reduction being made for the shape of the tank. 
Shear stresses in the concrete were provided for by stirrups binding together the upper 
and lower longitudinal reinforcement. The working stresses on concrete were taken at 
500 lb. in compression ; and on the steel in the stand, 5 tons in tension. In the tank the 
steel was stressed at 7^. tons. The whole structure is reinforced with square and round 
steel rods, varying in diameter from g to 4 in. The slabs forming the bottom oi the tank 
arc 6 in thick, and the walls or sides 12 in. thick at the bottom and g in. thick at the top. 

f. Materials. — The concrete was composed of i part of cement, 1% parts of coarse 
sand, and 32 parts of scoriaceous Andesite, crushed to a i-in. gauge. This stone was weak 
and porous. The Portland cement conformed to the British Standard Specification. Mild 
steel of 30 tons tensile strength was used for the reinforcement, but for the smaller work 
a good deal of wrought iron was employed, with a tensile strength of 24 tons per sq. in. 

I'/. Method'! of Construction. — The concrete was mixed fairly wet, and used at once; 
but in some cases, owing to the great height of the work, an hour may have elapsed 
between mixture and use. Care was taken to keep the steel bars in their proper position. 
Most of the reinforcement was bent to exact shape and laced together. 

V 111 . Failures or Deterioration. — iVo evidence of failure has occurred from any cause 
whatsoever. It would have been advisable to place an expansion joint in the supply and 
delivery pipes, both of which pass through the floor slab and are rigidly attached to it 
by a collar ; but so far no trouble has arisen from this cause. No tests of the finished 
tank were made, but it was filled as soon as the profiling was removed, about one month 
after completion. Some sketches are appended to the report to explain the placing of the 
reinforcement and the details of construction. 

General Descriftion of J ank at Mataroa. — A tank formed of reinforced concrete, 26 ft. 
in diameter and 9 ft. deep, with a square valve-chamber on side, destined to contain 
30,000 gallons of water. It was constructed in 1Q07 from the designs of the author, and 
is in first-class condition. No details of cost are given. 

/. Age. — Constructed in 1Q07. 

//. External Influences. — Exposed either empty or full to weather and sun and almost 
consant saturation. 

///. General Condition. — First-class. 

IV. General Features of the Design. — The tank was calculated as a tub, the hoops 
being steel rods embedded in the centre of the concrete sides, and considered as taking all 
the stress. The floor is entirely supported on the ground. The working stress on steel 
is taken at 6 tons per sq. in., and on the concrete in compression at 600 lb. The bottom 
of the tank is 6 in. thick, and the walls are 15 in. at the bottom, and 9 in. at the top. The 
concrete was composed of 1 part of cement to 5 parts of clean washed gravel, containing 
sufficient sand to make a watertight mixture. 

VI. Methods of Construction. — The concrete was hand-mixed and placed at once, or 
after an interval not exceeding half an hour. The vertical reinforcement was set in the 
fl<x;r concrete and stayed all round by framing. The horizontal bars were then tied to 
the vertical ones at projjer iieights before each layer of concrete was placed. The joints 
in the bars were made b\- lajjping for a length of 36 diameters, tying them and turning back 
the ends. The joints were staggered. 

VIII. Failures or Deterioration. — There arc no signs of raihirc from any cause, and 
no tests were made, but the tank was used a month after ( ompletion. 
In conclusion, we ;^ivc ;i report on 

An Injury to a Reinforced Concrete Packing House by Electrolysis. 
'Ihis rcpfjrt is [ircsciit* d by Mr. (i(()r>^c P( rrinc : — 

General Descriftion. — The jiropcrty in rjucstion is a large i)acking-house situated in 
Allentown, in the Slate of i'ennsylvania. It consists of a number of connected reinforced- 
concrele structures of tliree, four and live stories and h-asenicnt, with aljout 300,000 sq. ft. 
of floor space. 

Age. — 'J'he buildinj.;s uer-- < onqth I' <l in 0( tobrr, KyoG. 

External Influences. — The buildings are very damp owing to the acid vapours from 
the ren<lering iiroee^ses, etc., and also to the presence of refrigerating i)ipes. They are 
lighted from a jtrivale plant, situated in the basenu-nl of one of ihc buildings by 125-volt 
direct-current generators. I'.Iectrical tests showed that tlic inrrcnl would leave the 
positive wire at a i)lac<-, and travel some distance in the rein fort (Mneni, rejoining the 
negative wire further on. An ordinary grounfl-indi( ator llins showed nothing wrong. 
106 



fcKNoimSlK?Sil REPORT ON RHINFORCHD CONCRETE 

'Plii'it' is an I'li'clric slii'cl railway opi-rali'd Irnin oxiilicid t lol ley-wires passinj,' in 
front <)t till' packing-liousi'. ( )n lf>tinK, how ex <r, no a|)|)r(( iahU' (untnl from this source 
was found to enter thi- l)uildinK- 

/'rrsrn/ Conditii^n. — in the summer of kjo;, hori/ontal cracks a|)i)eare(l on the lower 
surface of the beam and girders, parallel willi the reinforced steel. The i)hotOKrai)hs 
shown in an article on the failure* are tvpii al ixamples of the injured beams throuf,dioiit 
the huildiu},'. Tlu^ (olumns were also aiTected, and there were several cylindrical columns, 
ai out jS in. in diametir and iS ft. hi^h, wdiich were cracked from top to bottom, a crack 
havin;j; fonne<i (>\ ev each \iTtical rc>d. Tlic-x" rods are about 5 in. fioin ihe surface oi tlie 
cone ret e. 

Fi'o/urcs of Design. — The beam and f,Mrder reinforcement consisted of j)lain steel 
l^ars, I in. in diameter alonji llie l)oltom, a number of the bars being turned up at the ends. 
The stiirups are of lin. 1)\- \\\\. steel. The main bars in ihe columns are of plain round 
steel. 

There are distributed throut,dic>ut the huilclin},' about 3,600 iron .sockets which are 
attached directly to the steel reinforcement. The sockets were used for sui)porling the 
woodwork for the trolle\-iracks used in handling the carcasses, etc., and for sui)i)orting 
the electric conduits for the lighting circuits. About 600 of these sockets were used to 
h.old the steel concluits carrying the electric wires, which caused most, if not all, the 
damage to the buildings. 

Materials. — The concrete used in the building was machine-mixed and excellent in 
quality. The Portland cement used was manufactured within a few miles of Allentown ; 
the stone used was limestone. The proportion of aggregate was i part of cement, 2 of 
sand, and 4 of stone. The pieces of concrete taken from the injured beams w-ere as sound 
as that of the uninjured portions of the beam, no api)arent change having taken place in 
the concrete. 

Failure or Deterioration. — There were about 3,000 lineal ft. of beams ancl girders 
showing cracks, and from some the whole lower surface of concrete had dropped oil, 
leaving spaces between the rods and the uninjured portion of the beams. 

Where the beams were damaged the most the intermediate floor slabs contained no 
cracks, the reinforcement not being electrically connected with the beam steel. 

The rods and stirrups were completely surrounded with scale of iron o.xide ranging 
from 1-16 to i in. in thickness. Some of the stirrups were completely destroyed and only 
oxide remained in their place. The oxide taking up a larger space than the iron caused 
cracking and fiaking-oflf of the concrete. The concrete where ruptured had the same 
appearance as it would if split with wedges. 

There were some concrete piers containing no steel under the cooimg-pipes in the 
cooling-room ; these were partially destroyed and crumbling. 

Remedies.^ — Since the publication of Mr. Brown's article further investigations have 
been made, and the following remedies have been carried out : — 

The water, gas, and sewer pipes have been insulated just inside the building wall in 
the basement. The sockets in the beams and girders have been connected by return wires 
which lead to the dynamo and terminate in an indicator board, each room having a drop- 
indicator. In case of an earth the indicator gives a warning, and the difficulty can be 
corrected. If it is not corrected at once the lights are automatically dimmed. 

Re-pairs. — In repairing the beams all loose concrete is removed, and the concrete and 
steel are thoroughly cleaned by sand-blast. After this is done i-in. boards are clamped 
to the sides of the beams to be repaired, and cement mortar to which a waterproofing 
compound has been added is blown on the bottom of the beam by compressed air. The 
trade name of the waterproofing material is " Starex." It is added to the mortar before 
placing in the machine. 

The bond between the new mortar facing and the old concrete is perfect, and the new 
material is very dense and shows no shrinkage cracks whatever. Mortar applied without 
the waterproofing substance showed shrinkage cracks and did not adhere to the old 
concrete. The machine used for depositing the mortar is a new and ingenious apparatus, 
and is doing ver}' excellent work. 

The old conduits have all been removed and new ones placed which are insulated from 
the structure. All junctions and joints being made waterproof. 

The structural details of the buildings are apparently of good design and the work- 
manship of construction is of the best, and the failure is not due to any such defects. 

* H. P. Brown, Engineering Xeus, Vol. 65 (igii), p. 684. 

t Ihe electrical tests are described in Mr. Brown's article. Experiment' indicating the relative 
effects ot alternating and direct current, etc., on electrolysis of reinforced concrete were given in a 
Paper by Mr. H. Barker and Prof. W. L. l^p>-on. Convention of .American Institution of Electrical 
L-ngineers, June, 1911. 

D 107 



HYDRO ELECTRICITY WORKS, CHESTER. 
C O 




la)NCBETEJ 



CONCRETE AND RE- 
INFORCED CONCRETE 

AT THE 

HYDRO ELECTRICITY 

WORKS, CHESTER. 



The a}K)ve works are erected upon the site 
of the old Dee Mills, which were in opera- 
tion from about i too to 1909. The old 
mills were erected upon the bed of the river, 
which is of sandstone rock. 

I-'or the purp;)se of the H\(lro Electric 
Works it was necessary to excavate the 
rock in the head race to a depth of 5 ft., 
and l<jr the draught tubes of the turbines, 
to enable them to discharge into the lower 
river, the rock was ex<\'i\aled lo a depth of 
15 fl. 

J he under-w alcr work forming" the 
foundations for ihc turbines and the walls 
ior liie turbine jjils are of concrele, slren*^- 
thened by ^-in. diamclcr reinlorcinj^' bars, 
as shown on the ^ciu ral arran<4cmcnt here- 
with. 

'Ihc j)i'0|><>ri ions for the, concrete are six 
to <;ne, loiu' |jarls •iJ^'J^re^atc, Iwo j)arls 
sand, and one |);ii'l (cmcnt. 'I lie ccnicut 
used is of the best f)uali!\ I'orll.md c( nicnl, 
of British manufaclurc, and in accor(lan<c 
with the particulars of I lie Hriiish .Standard 
Specification So. 12 foi nicdiuni scltinj^ 
cement. 

108 



An interesfing example of the usefulness 
of reinforced concrete and concrete in electric 
plants is that of the ivork recently carried 
out in connection 'with the neiv Hydro 
Electric Plant for the City of Chester, and 
of "Which ive gi've a feiv particulars belonv. 
We are indebted to Mr. S. E. Britton, City 
Electrical Engineer of Chester, for our par 
ticulars and illustrations, — ED. 




\ icw sliowirifj K(;inf()lciIl^^ Hais in i>osition for 
tli(; firsticourse of Concrete. 

TiiK Cm.sTi'.K Hydro liLixTRiciiY Wokks. 



r o, OON>TUlJrilC*«UlJ 
|.<V ENCUME.tJJlNC'1 -^ 



HYDRO ELECTRICITY WORKS, CHESTER. 



V\\v .s.iiul UM'd is cli'nn, sharp, and coarse ri\iT sand, comiKJScd ol grains 
\ai\ inj; in si/c which pass ihroui^h a J -in. s(iiiart* nu-sh. 

I he ai^i^rci^atc lor ihc ])lain t'onciclc is ol l)rol:('n I'cnniacnniau r and 
C'arroLj- stone, xaryinij' in size from h in. lo i .^ in. (uhes, and tlie aj^greg^ale for 
the reinforctment \aries in si/e Ironi '; in. to { in. cul)('s. 




View showing s:eel joists in Power House. 




View showing concreting of steel joists in floor of Tuibine Pits. 
The Chester Hydro Electricity Works. 

The power house walls are of red sandstone, lined with glazed brick. 
The roof of the power house is of reinforced concrete on the Kahn System, 
details of which are shown on the general arrangement drawing referred to 
above. 109 

D2 



HYDRO ELECTRICITY WORKS, CHESTER. 



[CDNCBETB 







c;^^^^.^:^^^^^ 



I lO 



f y, CONM kMKTIONAl. 



HYDRO ELECrRlClTY WORKS, ClIItSTER. 



The i)()\\('r h>)usr is <S() ll. loni; 1)\ J4 I'l. h in. wide, aiul, iiicasurcd from 
ihc 1)1)1 loin of llu- head raii', 3*) ft. liiL;h. It i.s mainly constructed of steel 




View sh owing concreting of Turbine Pits. 




View showinL" concreting for Turbine Pits and steel work for Sluice Gates in position. 
The Chester Hvdro Electricity Works. 

and concrete ; ihe exterior is faced with sandstone rock and the interior with 
glazed brick. The foundation is on sandstone rock. The under-water work 

I 1 1 



HYDRO ELECTRICITY WORKS, CHESTER. 



CQNCBETEJ 



forming- the head race, the three turbine pits and the tail race are of concrete 
and steel. On the external face of the down-stream side of the turbine pits 
are placed three cut waters and Gothic arches, these and the filling-in of sand- 
stone to harmonise with the adjoining bridge. The external of the above- 
water p;irt of the building, including the dynamo, switch room, and stores, 
is in sandstone, and contains twelve pairs of Gothic windows ; the interior 
is lined with glazed brick. The building is covered with a flat reinforced 
concrete roof covered with asphalte. There are three circular glass domes 
in the roof, which admit of ample light and add to the general 




Cross Section through Turbine Pit. 
The Chkstkk Uvdku ELKcrtJiciTY Works. 



beaulv <jf iht; l)uil(ling. I lie retaining wall bclwccn the biidge and the 
power hou^e and 121 ft. ol ri\er \\all beyond the powci- house has 
been entirely rebuill in ashlar, uilh sandslont; taken from the foundations of 
the <;ld mills. 'I hat part oi the old bridge \\hi(-li stands in the head race and 
former! [)art of tin; old mills has been restored, so as to liaiinonise with the 
general character of tiu- bridge, and a glance ;it the undertaking at once 
impresses one with the amount of ilioiiL;lit iM\ol\((l in carrying out this scheme 
and the improvement to the ;inicnities. 

A number of plu)togra|>liic iiliist i-;it ions :ii-e gi\cii in this article showing 



1 I 2. 



*»coivyrpuc-riaNAL; 

±y KNdlNKI.klNO — , 



lirnRO ELECTRICITY WORKS, CHESTER. 







View showing concreting oi Draught Fubes. 
The Chester Hydro Electricity Works. 



llu- concrcic .iiul rcinlorctnl corKTcIc 
work. Tlu-y iirc ;is follows : 

(i) I lie lornuTs in iK>.sili()n icady l-ir 

(-') 'IIu- siindslonc f.icin^'- of ihc 
(low M-slrciiin w.ill of \hv. j)o\vct Iiousl- ;iii(1 
the slu'C'tini^- ;iii(l reinforcing- bar.s in posi- 
iion lor the (irsl ( oursv of concrete for 
ihc walls of llu' turbine jjils. 

(3) Sk'cl joisls in llu- power house 
lloor lo (-arr\- I he turbines and j^enerators. 

(4) Concreting- steel joisls in floor of 
turbine pits to carry the down-stream 
wall of the j)()wer house. 

(5 and 6) Concreting- for the turbine 
•pits and the steel work for the sluice 
g'-ates in position. 

(7) The draught lubes being con- 
creted and the reinforcing bars being 
placed in position. 

(8) A wooden draught tube former 
being lowered into position. 

The contractors for the building and hy- 
draulic plant are Messrs James Gordon and 
Co., Knighlridcr Street, London, K.C. 




Showing Woodan Draught Tube Former being lowered into position. 
The Chester Hydro Electricity Works. 



i'3 



REINFORCED CONCRETE WHARF, ILOILO. 



ICQNCKETEJ 








'MS^^^^ 










A REINFORCED CONCRETE 

WHARF WITH GROUTED 

FOUNDATIONS; HARBOUR IMPROVEMENTS AT 

ILOILO, PHILIPPINE ISLANDS. 

The folloiving is an af^siract from an article by Mr, Wilson T, Ho'cve (formerly Assist. 
Ena'neer, Division of Port of Works, Bureau of Naiiigation, Manila), which appeared in 
" Engineering News," U.S.A., and ii'e are indebted to that journal for their courtesy in 
according permission for the reproduction. — ED. 

The citv of Iloilo is situated on the southern coast of the island of Panay, about 330 
miles south of Manila, and is one of the five ports of entry in the Philippine Islands. 
The principal export is sugar, which is shijjped to Chinese ports and to the United 

States. 

FACILITIES. 

The harbour of Iloilo comj)rises the Iloilo River and Iloilo Strait, the latter beini:^ 
a good anchorage at the mouth of Iloilo River, and protected by the islands of Panay 
and Guimaras. Previous to the |)resent improvements nearly all the foreign cargoes 
were handled bv lighters betwc en the ships in the Straits and the warehouses on the 
river. 

Iloilo River is not a river in the strict sense of the term, but is a tortuous tidal 
estuarv, the lower 9,000 ft. of which is navigable and available for shipping. This 
portion is in the shape of a huge letter S, and naturallx divides itself into three reaches, 
each approximately 3,000 ft. in length. In former times the lower reach was merely a 
channel through tide flats, but at various times in recent years this reach has been 
inif^roved bv dredging, the material being deposited on the banks on either side, until, 
at the present time, it exists as a ddinilc stream, 400 to 500 ft. in width, llowing between 
permanent banks and discharging into Iloilo Straits between two ri|)rajj jetties. 

The onl\- dr)cking facilities available previous to 1908 were on the middle reach of 

the river, where most of the warehouses are situated. A marginal street, varying 

in width from V' '^' ^''^ ^^■•> '-xt'-nded the whole length of this re.-u h, and it was sujjported 

on th<; river side b\' a light adobe-stone retaining wall founded on the natural soil at 

about low-tide level, and, eons<-c)uently, onl\ light irafl (ould moor directly alongside, 

steamers being obliged to stand off, and passengers and cargo handled over long stage 

planks betwren the wall and sjii],. The (Icplh on ihis reach was from 15 ft. to iS ft. 

at low tide. 

IMPROVEMENTS. 

The first intprovem<'nt at Iloilo und<i llic Ann rican occupation was to dredge the 
middle and lower reaches to |S f I . at low wal< 1, using the dredged mateiial to fill low- 
land on the left bank of the ri\<r, o|)|)osiic the ( ily, and an area on ihc right hank on the 
lower r<a(h, retaining the fill and |»rol<(ling the river i liann<l hy (l\Ues of small ri|)rap 
sionc {I'ul. I) and building ripraj) jellies on either side of liir rixcr at its mouth. The 
fill ,,p ij,,. left hank of the lower reach is now occupied l)\ llir Iloilo terminal of the 
l'ana\ Division of ilw l'liili|»pin<- Railway ConipaiiN, a line 70 miles long, terminating 
at Cai)!/., on the noiili coasi of the island ol Tanay. Tlw opposite fill has become a 
valuable site foi- wart-houses. 

"4 



(i 



C-ON.vrUn KTION A 1 
V b.N( • 1 N KL-WtNCi — 



REINFORCIin CONCRETE \VIIARl\ ILOII.O. 



? 




Fii^. 1. Stone Dyke Backed by Mats of Split Bamboo. 
Harbour Improvements, Iloilo, Philippine Islands. 



'Vhv pit'sciit ini|)r(.\timnt, iiiuli rt.iUcii in i()(.S, coiilciiipl.ilcs ;i ddinilc (1( \< lopniciU 
ami i)r()viilcs .i 15-tt. d. ptli .il low w-iI'T in ihc u|)|)«i- i(;i(li, iS fl. in llic niiddlr r<;i(li, 
and J4 ft. in the lower H'nch. 'ihc ciiiirc rixcr w.is dcixiK d lo lh(s<' li^uics in kjio. 

TImsc d(|)tlis a I «• 
prohahlv ihf ^rcalcst 
which il is advisahh- 
lo altcnij)! lo main- 
lain in lh<' rc'^pcctivt: 
reaches. 

T h (' material 
dredi^ed from t h e 
river at this time was 
used to extend the 
|)reviously lllled areas 
owned b\ the Insular 
( jovernmenl, and lo 
improve several low- 
1\ in<^ areas wilhin the 
city, and also to re- 
claim a considerable 
area of beach on the 
left bank of the river, 
frontini4 Iloilo Straits 
and adjoinin<4 the 
railway terminal. It is proposed to develop this area by buildinij a series of docks and 
slips where steamers drawing 30 ft. can berth, and to lease the property for warehouses 
or other puri)oses at the proper time. 

QUAY WALLS. 

For the quav walls a retainini^' wall was first built, but was later followed by a 
reinforced concrete wharf. 

CONCRETE 
RETAINING WALL 

The second step 
of this improvement 
consists in the build- 
ing of suitable quav 
walls along the river 
as funds become 
available, and t h e 
most urgent require- 
in e n t was the re- 
placing of the old 
wall on the middle 
reach by a n e w 
struct ure approxi- 
mately parallel to it 
and in front of it, 
alongside of which 

vessels drawing 18 ft. pjg 2. old method of Loading Su^ar : ' uan-gom?; Steamers, 

could lie at all stages Harbour Improvements, Iloilo. Philippine Islands. 

of tide, at the same time providing a marginal street with a uniform width of 80 ft. the 
whole length of the improvement {Fig. 3). 

»'5 




REINFORCED CONCRETE WHARF, ILOILO. 



ICQNCBETEl 



A contract was let by the Insular Government for the construction of a gravity- 
concrete retaining wall upon timber piles, but after doing a very small amount of work 
and making unsatisfactory progress, the contract was annulled, the contractor's plant 
purchased, and the work was comj)leted by Government administration. 

When this length of retaining wall had been completed a point was reached where 
the wall type of construction was becoming more expensive and troublesome on account 
of the proximity of the old retaining wall. The new wall has a bottom width of 15 ft. 
at the depth of iS ft. below low water, and as it was necessary to dredge to that depth 
and width, the bank slope was not able to carry the old wall and the street behind it 
without considerable expensive shoring, and it was desirable to leave the old wall and 
its well compacted fill intact if possible. The marginal street is occupied its whole 
length with storehouses and offices, and carries a heavy traffic, which could not wholly 
be diverted during construction, and it was therefore essential to so conduct operations 
as to leave the street in use. 




Fifi. 3. Completed Quay and Marginal Street along Iloilo River. 

HaKIJOI R ImI-KOVKMKNTS. iLrill.O, PlIILII'l'INK ISLANDS. 

REINFORCED CONCRETE WHARF. 

Plans were accordingly jHcparcd f(jr a icinlorccd concrete wharf structuic which 
would take advantage of existing conditions to their fidlesl extent. The wharf 
consists ess(;ntiall\- of a series of transverse gir<iers spaced 10 ft. apart, carrying a 12-m. 
reinforced concrete floor. The outer ends of the girders are supjjorted upon reinforced 
concrete columns 24 in. in diameter and H) It. S in. long, cast in the \ard, and s(>t in 
place with a derrick upon a prei)are(l timber |)ile footing 17 ft. S in. below low water. 
The inner ends (A the girflers are (arried h\ con( icte pedestals at 2 ft. ;iho\'e low water, 
built against the old wall and carried onl\ to the natural slope of the hank. 

Rear Fooliuf^s.- ICach rear pedestal is suppoitrd l)y from lour to six timber piles, 
at least two of wlii<h are dri\-en on a halter, the heller to resist any hoii/.ontal thrust 
that may come from the old wall. I his group of piles is diixcn to a total bearing of 
So tons it h( ing alwa\s desired to drive each j)ile to 20 tons if possible, but as it was 

116 



fc,,ooN>Tync-rioNAii RHINFORCHD CONOR HTE WHARF, ILOILO. 

froqiUMilK ini|)()ssil)U' to secure piles of suflieit iil It iij^lh lo (ievelo|) tliat he.irinj^, ( iiou^h 
extr.i piles were Mdcled to insuic the lol.il n tjiiii<(i hearinj^ |)owei- per ^loup. 

These pedest.ils \;ir\ in si/e .iiid position .leeordini^ to the .di^nnienl of th<' ol<l u.dl 
.'ind the luiinher of piles necess.iry |)er i^i'onp, hiil the si/.e was usually dependent upon 
the position of the halter |)iles whieh were dii\-en as close to the old wall as the leads of 
the dri\'er in the hatlt red position would allow. ( 'onneetinj^ tlu' pedestals is a concrete 
curtain wall j fl. in thickness, which serxcs to strengthen the old wall. The curtain 
wall was huilt to the i^rade of the pedestals monolithic with them; al)o\c that i^rade 
it was poured at the same time as the i^irdeis and lloor. 

Fro)}! Fooliiii^s. — The most intei'estinif and important featuic of the work was th(; 
construction of the front foundations, 'idle outer edj^e, or front of the wharf, as stated 
above, is carried h\ the lin(> of reinforced concrete columns, spaced lo fl. a|)art, one 
under th(- outer end of each of the transverse f^irders. This line of columns is so j)laced 
as to i;i\'e a imiform width of street from the front of the wharf had-: to the huildinj^ 
line of 80 ft., and as there was considerable variation in the old street width out to the 
irregular lin(> of the old wall, the sjjans of the main girders vary from 20 to 27 ft. The 
latter length was the maximum nominal sj)an allowed in the design. 

Each column is carried by a cluster of piles whose total bearing is not less than 
60 tons. It was attemi)ted to drive each pile to a bearing of 20 tons, and this was 
usually obtained, but often four piles, and sometimes five, were required. The reason 
for requiring but 60 tons per grou]) in the front footings while those in the rear were 
expected to develop 80 tons was due to the fact that it was uncertain what loads might 
come to the latter through the weakness of the old wall, and which those piles would 
have to carry in addition to the direct load from the new structure. When only three 
piles were required they were driven at the apexes of a 20-in. equilateral triangle. 
When four piles were necessary they were driven at the corners of a 20-in. square, and 
if a fifth pile was required it was driven in the centre of the square. It could usually be 
foretold how manv piles would be required for any column by the penetration secured 
in the last cluster driven, and if the number were under-estimated those driven were at 
once sawed off at the proper grade, their positions carefully located by plumbing above 
the surface, and the additional pile needed was then driven in the most favourable 
position to give good s])acing in the cluster. Since it is seldom possible to drive a pile 
to the exact location required it was necessary to use more than ordinary care in spotting 
these piles, and to hold them during driving, in order to keep them within proper limits. 
Frequentlv after locating the driven piles it would be found that one or more were 
so far out of position as to necessitate the driver returning to put in extra piles, those 
too far from line being excluded entirely from the foundation. 

After the piles were driven and cut off they were enclosed in a circular sheet-iron 
casing, re in- metal, usually 54 in. in diameter and 4 ft. high, so placed that its top 
w^as 2 ft. above the pile cut-off. To support the casing on the bottom it was necessary 
to throw small riprap stone around the piles until a firm bottom was made. To set 
the casings a wooden frame was provided, 4 ft. square and 22 ft. long, to the bottom 
end of which the casing was fastened with wire. The frame, or template, carrying 
the casing on its low^er end was then picked up by the derrick and set in place, a diver 
guiding the lower end to ensure that the casing was at all points at least 6 in. distant 
from the side of any pile, while the top, being always above water, was directly under 
observation for line and grade. A gauge, with its zero mark 16 ft. above the top of 
the casing, was fastened to the frame, so that at any stage of tide the casing was 
easily set at the proper grade by noting that the gauge on the frame read the same 
as the water height on the permanent gauge. 

After the casing was set to line and grade, concrete was placed in it by means of 

117 



REINFORCHD CONCRETE WHARF, ILOILO. 



[concbete; 



a canva. bag openin- ai the bottom, to a point 6 in. below the tops of the piles When 
the concrete had set a diver cut the wires holdin.^ the casing to the frame and the latter 

was removed. , , j i 

Grouted FounJatious.-^Whvn ihr column was about to be placed gravel was 
deposited in the casing to the grade of the bottom of the column, and the latter was then 




Fig. 4. View of Completed Reinforced Concrete Wharf. 




i-iK. J- \i<:w Slii»wiii^i lii .1111 :.ii<l I lour KuiiifoiceiiKMil. 
HakhouR Imi'KOvkmknts, li.oii.o, i'liii.ii'iiNK Islands. 

(arcfulh s<l to line and gra.lc and br;i( < <1 to the falsework, it icsling meanwhile u|)()n 
the gravel in the casing. Thin ( emeni -^roul was then poured iiilo the gravel through 
a i-in. i)ip<- (arrying a funnrl at its upp. r end. .\s no pressure was used to force the 
grout into the gravel except the sialic h* ad Ix l\\e( n the surface of the water and the 
upper end of thr- pi|)e, whidi was never gi eater than about S ft., it was found necessary 
to move the pi|>e around aixl grout at dilferent points in the L',r;i\el to insure that the 
gravel was thoroughly (eniented. .\fter the gravel iirst placed was thus grouted, 

Il8 



'o, CTONyiVUCTlONAH 



REINFORCED CONCRETE W/IARE, ILOILO. 



more i^i;i\rl was dcposiltd aioiiiid (he column to luaUc a la\tr ahoiil i It. tliick, wliicli 
was then i;rout((l as Ixloif. It was found necessary to thus j^rout the j^raN'el in lavcrs, 

hecause in atteinptinj^ to force the 
^routinj^ pipe throuj^h any considerahle 
thickness of gravel it became cloj^j^ed, 
.:^^ and Ihc pressure was not ^real enou^l'' 
to clear it. When the casinj^ had hec n 
lilled with concrete in this mannei', and 
had sei at least t went \ -four hours, tlv 
liolJoA interior of the column was 
punijx d free of water, and then lilletl 
with concrete. The jnnnpin^ of the 
interior served as a test of the j^routin^, 
for if any part of the gravel had not 
been thorou<^hly scaled, water would 
soon ha\e appeared inside the column, 
and indicated defective work. All the 
columns were easil\- pumped b\' a small 
hand pump, and remained dry for an 
hour or more, before fillini^' with 
concrete. 

This method of building these foot- 
ins^s was entirely satisfactory in everv 




Fig. 6. A Reinforced Concrete Mooring Post. 
Harbour Improvements, Iloilo, Philippine Islands. 

but on account of the richness of the 
concrete, and the unavoidable waste, 
due to some of the grout escaping, it 
would be expensive in a very large 
mass. In this case, where it was neces- 
sary that a perfect result be obtained, 
several advantages are apparent. It 
obviated placing concrete under water, 
and it excluded the necessity of pump- 
ing and the coffer-dani method, which 
would have been out of the question 
for such small foundations. 

The setting of the columns was 
rendered simple, as they were placed 
on the gravel in the casing, and so had 
sure support during the operation of 
filling the casing. The difficulties of 
setting columns on a bed of green con- 
crete under water must be evident. The 
manipulation of the column while 
attaining line and grade would so 
agitate fresh concrete as to cause it to 
separate, or it would be necessar\" to 
support the column from above and 
then bring the concrete up to it. In 
the method described the column was 



way, and there are probably man\ 
similar cases where small well-confined 
foundations can be similarlv treated, 




Fig. 7. Concrete made under water. 
Harbour Improvements, Iloilo, Philifpine Islands 

119 



REINFORCED CONCRETE WHARF, ILOILO. 



ICQNCBETEJ 



lowered directly on to soft gravel which- had previously been brought to the proper 
grade. If the column proved to be too low it was raised slightly and more gravel 
poured through the interior of the column. If too high, the column was dropped upon 
the gravel to compact it, or it was twisted and moved to work it into place and nothing 
was disturbed thereby. 

That good concrete was made by this method was proved by experiment, and it 
is thus described in a report made at the time : 

An empty cement barrel {Fig. 7) was lowered into the same depth of water in which 
the footings are made, gravel placed therein by means of a 6-in. pipe to a depth of about 
S in., and then the grout |)ipe inserted into the gravel, care being taken to have the pipe 
coincide with the axis of the bariel. The irravel was then grouted in the same manner as is 

done in the foundation, 
more gravel placed in 
the barrel to the depth 
of about 12 in., and 
more grout poured, and 
so on until the barrel 
was filled with gravel 
and grouted. The 
sample was taken from 
the water after about 
40 hours, the barrel 
was cut away, and the 
result was an entirely 
satisfactory block of 
concrete. Some very 
small pit holes ap- 
peared in the surface, 
but as a whole the sur- 
face was as smooth as 
is generally obtained in 
ordinary form work. 
The result shows that 
the grout will flow 
freely for at least 8 or 
9 in. in all directions 
from the pipe. Eight 
buckets of grout were used in the barrel of gravel. 

Backfill.— After the columns were set, riprap was placed along the front line of the 
wharf to a depth of 16 ft. below low water, and the slojx- back-filled to the tops of 
the rear foundation bUnks with rijHap and mud. The latter was to insure that the 
piles supporting the blocks would ]>c fully j)r()lected from teredo, while the rii)rai) was 
to make a stable and f)ermanent slojx- and to |)re\-ent scour. 

Superslnnliirc. The construction of the supersliiiel m c olTcred no unusual 
problems and followed th<- usual jjracliic in reinforced coiKrele. A len<^nh of 20 ft. of 
wharf, or two sjK'ins, was made at e; eh o|)eralion, joints being broken in the centre 
(A the llrKM- sjn-nis, a portion of the slab being figured to .k l w ilh the girders as a T-beam. 
.\t expansion joints ihr- break was made at the (dge of the girders through (he floor 
thence along the rear side of the spandK I ,ind ihrongh the (cnlre of the arch. The 
concrete nuxjring frosts il'i^. 6) were cast in placr at I lie same time as the wharf lloor. 
They are hH:al<d Oo ft. apart the whole h n^ih of the wh.irf. Mooring posts of concrete 
have been used at various places on work done in the Philippines, and have proved 
satisfactory. .As each niof)ring post contains less than one-third of a cubic ^ard of 
concrete, and about 100 lb. of reinforcing steel, they aie nuich cheai)er than the ordinary 
cast-iron posts or cleats. 

F(ils('7uork. The whole consti ik lion was carried out b\ the use of falsewoik 
Bents of three; or f(;ur piles each, as lecjuired by circunist.uices, were driven to i«rade 
I 20 




Via. 8. View of Pile Driver. 
Harbour Improvements, Iloilo, Phimpi'Ink Islands. 



^^'SGf™?iK?t3 REINFORCED CONCRETE WHARF, ILOILO. 



U) fl. a|);ir( ini(l\\;t\ hitwccii j^irdci s, .iiul i;i|)|)((l ;il 7 fl. ;il)C)\c low water. I'^roni llicsc 
raps the piles wcic (Irixcn for foundations hy a skid dri\(r. As the pile driver finished 
its work and nio\(d ahead, ihe caps were removed, the piles cul oil at 4'5 ft. aho\c 
low watei- and recap|)ed. h'roni this trestle as a woikint^ |)latloini the (oliinins were 
set, and it also carried the forms for the superstructure. 

It was not feasihle to operate the drix'er on this low trestle, as it was not only helow 
hii;h tides twice e\( r\ (la\ , hut the drix'ei" had to work partially on the old street to 
mancvuxre for position to drixc the halter piles, hence it was necessary to have th<- 
trestle at that elevation for drixini;, while to caiiy the forms for the superstructure 
it was necessarx to cul off helow the imdei-side of the deck. All hut the outside piles 
of each henl w c ic lost, it l)ein<4 of course imjjossihle to recover them after the super- 
structure was l)uill. A feature of the falsework was its arrani^emeiU whereby a 
sup|)ort was left under the centre of the Hoor slab after the remainder of the forms were 
removed. I-^orms were remoxcd from the i;irders and slabs after seven da)s, but the 
centre sujjport was left at least fourteen days, and in most cases lonj^er. 

Pile Driving. — Generally the jjile driver used was of special design in order to drive 
the batter piles {Fig. 8). The head block was supported by the ordinar\- four-lej^j^ed 
tower, 36 ft. hii^h, but the two forward legs were spread outward at the bottom to give 
a batter of one horizontal to five vertical. Two brace legs extended backward from the 
vertical legs at the rear of the head block. The head block overhung the front battered 
l(>gs about fifteen inches and carried the swinging leads. The leads were made as light 
as possible consistent with their duty and were of single 3 in. by 12 in. yellow pine, 
with angle-iron hammer guides, and were 65 ft, long. They were connected together 
at the bottom by a timber yoke, and at three other points in the lower half of their 
length bv yokes of strap iron, and were fastened again at their tops. No connections 
were possible in the upper half-length of the leads as they had to be free to slide up and 
down over the sheaves in the head block. 

Concrete. — Concrete was mixed bv hand and shovelled directly into the forms. The 
concrete in the girders and floor was mixed on the floor last in place. The bottom of 
the main girders was only 2 ft. above low water, but no attempt was made to make the 
forms for them watertight, work being so arranged as to begin concreting on a falling 
tide as soon as the form could be cleaned after the tide had left it, and by the time the 
rising tide had reached the concrete it had been in place long enough so that no injury 
was done to it. 

The concrete in the rear footings was deposited under water by means of a 6-in. 
tremie, and it ])roved more satisfactorv to finish the tops of the pedestals under water 
at high tide, than to finish them in the dry at low water. The top of the finished 
pedestals was only 2 ft. above low water, and when it was attempted to finish them 
in the drv, the wash from passing launches so washed the concrete as to make it 
extremely difficult to get good results. 

Sand and gravel were piled always near the mixing platform, and were brought 
to it bv men working in pairs carrying the materials in half cement barrels slung by 
wire from a pole across their shoulders. 

All reinforced concrete w^as mixed in the proportion of i : 2 : 4, while that placed 
in the foundations under water was proportioned i : 2^ : 5. 

Labour. — Nearly all the labour on this work was done by Filipinos, under a single 
American foreman. There were on the rolls a Japanese blacksmith, and at times 
three or four Japanese or Chinese blacksmith helpers and carpenters. The pile-driver 
engineer was a Filipino, and as good an operator as could be desired, although he 
was not alwavs as capable of keeping his engine in condition, or of making repairs 
as a white. Night watchmen were East Indian Sikhs, who had usually seen service in 

121 



REISFORCED COSCRETH WHARF, ILOILO. 



[CQNCBETE 



3riti>h Indian Arnn ; th.s. nu-n are fcnuul .vnv.h.re in the East, and seldom work 

Nvrll as all harbour xvork and the liohthou.e work in the 



the B 

except as watchmen. 




bv Mr. Harrv A. Thompson as Assistant Kn.Liineer in local char^^e 




Fi^. 9. Concrete Columns in Castinfi Yard with Assembled Iron. 
Harbour Imi-rovements, Iloilo, Philippine Islands. 



I 22 



■ VKNCilNl-l WlNti — , 



SOME FALLACIES IN CEMENT TESTING. 




ffg 



"'''j''-''""'''!'""''''''''"* 



RECENT VIEWS ON 
CONCRETE AND REIN. 
FORCED CONCRETE. 



THE CONCRETE INSTITUTE, 




J 



It is our intention to publish the Papers and Discussions presented before Technical 
Societies on matters relating to Concrete and Reinforced Concrete in a concise form, and 
in such a manner as to be easily a'vailable for reference purposes. 

The method "we are adopting, of dividing the subjects into sections, is, roe belie've, a 
neiv departure. — ED. 



THE CONCRETE L\STITl'TE. 

SOME FALLACIES IN CEMENT TESTING. 

By W. LAURENCE GADD, F.I.C.. M.C.I.. etc. 

TJic following is an abstract of a paper read at the Forty-first Ordinary General Meeting 

of the Institute. 

INTRODUCTION. 

The object in this paper is not so much to question the accuracy of the 
testing performed by inexperienced operators as to draw attention to what are, in my 
opinion, fallacies underlying some of the recognised or suggested processes of testing 
Portland cement ; and at the outset I find myself at variance with the British standard 
specification itself. 

The standard specification stipulates that before any sample of cement is submitted 
to certain tests it " shall be spread out for a depth of three inches for twenty-four hours 
in a temperature of from 58 to 64 degrees Fahrenheit." 

The object of this procedure appears to be twofold — i.e., (a) to cool the cement to 
the normal temperature of the atmosphere, and (b) to obtain conditions similar to those 
governing cement which has lain in sacks or casks for two or three weeks — i.e., during 
the possible period between shipment and use. 

As regards (a) this can be verv simplv done without exposing the sample to air 
As regards (6) I have made the following experiments : — 

EFFECT ON SETTING TIME OF STORAGE IN SACKS. 

Two large samples of cement, one freshly ground and the other ground about a 
month previously, were filled into sacks, tied up, and ])ut aside in the warehouse at 
each of six different factories on the Thames and Medway and in the Isle of \\'ight. 
Samples A, B, C, D, E, and F were rotary kiln cements; samples G, H, J, K, L, M 
were chamber kiln cements. 

Specimens of all these were despatched to me at the time of filling the sacks. After 
two weeks the contents of the sacks were thoroughly mixed and a second set of samples 
again sent to me, the remainder of the cements being returned to the sacks and stored 
for a further two weeks, when the same procedure was again gone through. 



123 



THE COXCRETE INSTITUTE. 



(CQNCBETEJ 



The three sets of 



ampU's were tested for setting' time with the following" results 
TABLE A. 

Sfttixg Time (^hNUXEs). 



Cement. 



Date 
Ground. 



iirst Samples. 



Initial. 



Final. 



Second Samples. 



Third Samples. 



Initial. 



I'inal. 



Initial. 



Einal. 



A 

B 

C' 

D 

E 

I- 

G 

H 

J 

K 

1. 

M 



8/6/13 
4/7/13 
2/6/13 
4/7/13 
6/6/13 
5/7/13 
2/7/13 
25/5/13 
7/7/13 
3/6/13 
7/7/13 
'( o 13 



no 


170 


35 


125 


60 


120 


105 


210 


70 


205 


60 


120 


102 


357 


35 


365 


60 


240 


135 


330 


60 


375 


90 


285 


140 


335 


100 


400 


135 


420 


162 


402 


185 


455 


165 


480 


105 


255 


235 


445 


300 


480 


65 


185 


180 


435 


300 


480 


70 


130 


35 


155 


Not recei 


ved 


80 


170 


55 


235 


Not recei 


ved 


75 


405 


55 


370 


90 


360 


'"^5 


'^ ■^ 


43 


345 


60 


270 



EFFECT OF AERATING IN LAYERS THREE INCHES DEEP. 

.Samples of the cements as received from the works were laid out for twenty-four 
hours, in accordance with the British standard specification, and then tested, with the 
following results : — 











TABLE 


B. 














Sitting Time (Minutes). 






1 


I'irst Sample. 


Second Sample. 


Third Sample. 




1 
As 


Aer. 


Aer. 


As 


Aer. 


Aer. 


As 


Aer. 


Aer. 




Received. 


24 h. 


7d. 


Received. 


24 h. 


7d. 


Received. 


24 h. 


7d. 


A 


I no ' 


60 


75 


I 35 


63 


40 


I 60 


60 


33 




I-' 170 


. 165 


225 


F 125 


213 


145 


F 120 


133 


70 


B 


I 105 


55 


55 


I 60 


70 


45 


I 60 


43 


33 




1" 210 


145 


160 


1- 150 


205 


120 


V 120 


120 


70 


C 


I 102 


50 


55 


I 35 


30 


20 


I 60 


30 


13 




I" 357 


365 


430 


!•' 365 


365 


245 


L 240 


233 


240 


I) 


I 135 


70 


65 


I 60 


55 


30 


I 90 


90 


45 




J" 330 


430 


440 


1- 375 


445 


43" 


F 285 


330 


430 


E 


I 140 


75 


75 


I 100 


95 


85 


I 135 


105 


105 




!■" r.5 


315 


435 


b 400 


380 


505 


1" 420 


375 


470 


1 


I l(>2 155 


145 


I 185 


190 


105 


I 165 


165 


163 




1- 402 4V> 


445 


1- 455 


430 


3KJ 


I' 480 


54« 


510 


G 


I 105 100 


20 


I 235 


185 


13 


I 300 


210 


10 




I" 255 1 340 


123 


1- 445 


425, 


1 10 


F 480 


480 


50 


H 


I 65 1 45 


<) 


I 180 


165 


13 


I 300 


273 


15 




!•■ 185 200 


83 


!• 435 


360 


90 


F 480 


530 


55 


J 


I 7" 50 


23 


1 35 


45 


10 


— 


— 


— 




I J ■/> 1 10 


120 


I' 155 


233 


95 


— 


— 


— 


I< 


I ho 1') 


9 


I 55 


3<' 


10 


— 


— 


— 




1- 170 XI5 


47 


!• 235 


200 


55 


— 


— 


— 


L 


I 75 ; 60 


Ko 


I 55 


3" 


95 


I 90 


73 


103 




!•■ 4"5 


420 


365 


!• 370 


410 


410 


!• 3O0 


34 3 


440 


M 


1 I H5 


(>5 


(>(> 


I 45 


55 


25 


I 60 


()() 


103 




1 ]•■ 22'i 


2f><) 


'>,()') 


1' 345 


1 370 


If»r) 


!• 270 

1 


3 13 


2f>S 



The results of iIk- t<-sts show lliat llnri- is no rcl.iiion Ixiwccn the (Tfects of 
ai'-rating cem<iit for iwenty-four hours and storing in sacks for two weeks or a month; 
further that tin- setting tinn- is dirferently affected when tlu' same cement is aerated 
or stored in bulk in (liffer<nt localities or at dilf( r< iil pf liods. in some cases the effect 
of twenty-four hours' aeration is the (i|)p)Osite to that pnxluced by storage; and storage 
or aeration at one period has an opf)Osiie effe( I to storage or ai-ration at another [)eriod. 



!24 



J, cTONyrkM KTiON A l; 

AtN(.lNKt IJINC. — 



SOME FALLACIES IN CEMENT TESTING 



TABLE C 
An:u\ii<)\ \-n\i TwicNTY-ForR Hours comi>aki;i) with Stora(;k in Sacks for Two Wkkks ; 

I'.lMl 1 ON SlllINC. TiMI SHOWN IN MiNUII'S A( C I- I.I- RA II; I ) OK Rl lAKDI I). 







J'irst 'Iw 


W 


'I'Us. 






Second 


wo Weeks. 


— 


Twrnl\-lour Hours 
■ Air. 


Tw 


Weeks Sack. 


Twenty-four Hours 
Air. 


Two Weeks Sack, 




Inilial. 


1-iual. 


Initial. 


I'inal. 


Initial. 


I"inal. 


Initial. linal. 




a. r. 


A. R. 


A. 


R. 


A. R. 


A. R. 


A. R, 


A. R. A. R 


A 


50 — 


5 — 


75 


— 


•15 — 


— 28 


— 88 


— 25 5 — 


B 


50 — 


65 — 


45 


— 


60 — 


10 


— 55 


No change 30 — 


C 


65 — 


— 100 


(^7 


— 


— 8 


5 — 


No change 


5 — No change 


D 


52 — 


— 8 


75 


— 


— 45 


5 — 


— 70 


— 30 


90 — 


E 


Gs — 


20 — 


40 


— 


— 65 


5 — 


20 — 


— 35 


— 20 


F 


7 — 


— 38 


— 


23 


— 53 


— 5 


25 — 


— 5 


25 — 


G 


5 — 


— 85 


— 


130 


— 1 90 


50 — 


20 — 


— 65 


— 35 


H 


20 — 


— 15 


— 


115 


— 250 


15 — 


75 — 


— 120 


— 4 5 


J 


20 — 


20 — 


35 


— 


— 25 


— 10 


— 100 


Not rec 


eived 


K 


40 — 


55 — 


25 


— 


— 65 


5 — 


35 — 


Not rec 


eived 


L 


15 — 


— 15 


20 


— 


35 — 


5 — 


— 40 


— 35 


10 — 


M 


20 — 


— 40 


40 


-I 


— 125 


— 10 


— 25 


— 15 


75 — 



This appears to me to effectively dispose of the somewhat prevalent idea that 
chanj^es in setting time are due to some inherent property of different cements. The 
erratic behaviour found is common to all the samples tested, the composition of which 
varied within considerable limits, the lime contents, for instance, rangini^ from 64 to 59 
per cent. 

The retardation or acceleration of setting time on storage or aeration cannot 
therefore be due to peculiarities in the cements themselves, but must be due to chemical 
changes brought about by the absorption of some constituent present in the atmosphere. 

Cement has a strong affinity for moisture in the first place, and for carbonic 
anhydride in the second place, and these constituents are present in the atmos])here in 
variable proportions at different times and in different localities. 

From former experiments and reasoning, I have held the opinion that absorption 
of moisture results in a retardation of setting time; whilst absorption of carbonic 
anhydride produces an accelerating effect. Cement exposed to both inlluences will 
therefore have its setting characteristics affected one way or the other according to the 
relative amounts of moisture and carbonic anhydride absorbed, the net effect being the 
resultant of the two opposing forces. 

In order to test this theory, I have made some laboratory experiments, where the 
conditions can be under control and standardised, which is rarely possible in so-called 
" ])ractical " tests. 

The results indicated that pure dry air has no effect upon the setting time ol 
cement, the loss constituents remaining practically constant. 

On the other hand, the effect of moist air free from carbonic anhydride is distinctly 
marked, although the percentage of moisture absorbed is comparatively small. 

The acceleration of setting tinie b)' absorption of carbonic anh\"dride is clearly 
proved. 

Some further ex])eriments were made with a cement specialh' obtained, ground 
from fresh rotatory clinker without any addition, in the form of gypsum or steam, for 
the purpose of regulating the setting time. When received this sample had a practically 
instantaneous set, and could not be gauged with 30 per cent, of water. 

In this case the cement was subjected to successive treatment, a portion being 
withdrawn from the tube for chemical and setting-time tests after each experiment, 
the remainder being subjected to further treatment. 

I do not put forward the results obtained from these tests as final, but the results 
already given seem to clearlv indicate that the change of setting time which a cement 
undergoes on exposure to air depends entirely upon the relative amounts of moisture 



E2 



12 



THE CONCRETE IXSTITUTE. [CQNCBET S 



or carbonic anhydridt- which it absorbs. Therefore to aerate cement before siibniitlini; 
it to a setting-time test is a misleadins^ Oj)eration, 

FINENESS. 

The British standard specification stipulates that the fineness of grinding shall be 
such that not more than a certain i>ercentagc of residue shall remain upon a sieve of 
a stipulated mesh, under the conditions of the test. It is obvious that the most 
important point in this connection is to ensure that the sieves used shall be of standard 
and definite dimensions, and this is provided for by the following clause : — 

"The sieves shall be prepared from standard wire, and the diameter of the wire for the 
5776 mesh shall be '0044 in. and for the 32400 mesh '002 in. The wire cloth shall be woven 
(not twilled), the cloth being carefully mounted on the frames without distortion." 

The standard specification therefore Stipulates that for the first-named sieve there 
shall be 76 warp and 76 weft wires of a definite diameter ; and for the second sieve 
180 warp and 180 weft wires of a definite diatneter per square inch. 

When sifting cement through a sieve to obtain the proportion of particles too large 
to pass through the interstices between the wires, the size or area of the individual 
holes appears to be the only condition of importance ; and it is to be assumed that the 
intention of the framers of the specification was to ensure this condition being standard. 

If a definite number of wires of a definite thickness be equally spaced throughout 
the unit of measurement, the spaces between the wires will be of definite and equal 
area ; but the weaving of wire cloth has not yet attained such a standard of excellence 
as to ensure that the wires (especially in the finer counts) are spaced equally throughout 
the piece, or even throughout any individual inch. 

I submit that the size or area of the holes in a sieve is the real standard and should 
be stipulated, the actual diameter of the threads, or their precise number per inch, being 
of secondary importance. 

In the course of my duties, it falls to me to examine and to accept or reject 
numerous pieces of sieving cloth for use in a number of cement works and testing 
laboratories, and I have formulated a specification for my own use which aims at a 
standard sieve, whilst at the same time recognising and allowing for the great difficulty 
o{ wea'.ing cloth of this nature with extreme accuracv. 

This specification, for iSo^ sieves, I state as follows : — 

1. The standard area of the holes in inches is '003552, 

2. The equivalent mesh, calculated from the actual average area of the holes, 

as measured, shall fall between 1762 and 1852, 

3. The mean variation from the standard width of holes shall not exceed 

10 per cent. 

4. S(){ more than 10 per cent, of the holes measured shall exceed a variation 

(A 15 p(-r cent, from standard. 
Ancjther j>c)int which ajjpears to be overlooked is the size of the sieve itself. ^Khe 
British specifjraticjn stij>ulates that 100 grams of cement shall be sifted for a period 
of fifteen minutes, but does not specify the total area of the sieve to be used. I have 
.seen in use sieves varying in siz(; from 4 in. diameter to () or 10 in. square; and it is 
obvious that the same weight of cement, sifted for the same period of time, will be 
morr; effectively sifted over a larger area than over a smaller one. 

SPECIFIC GRAVITY. 

The specific gravity test is now used ifi pl.icc of ihc old mdliod of la]<iiig the weight 
j>er striked bu'-liej, which has for some lime been discredited. 

']"ln- weight per bushel had no real bearing upon or rel.ilioiisliip lo the de<>ree of 
calcination, but was rhielly influenced by t!i< lim ik ss of grindin'f. 

The specific gravity test is still retain. <j in ihr Rritlsh standard specification and 
is considered by most people lo fullil llw fmutioris loim.rlv altribulcd to th(> bush(^I 
weight test- viz., to delect the degree of burning to \vhi( h the clinker has been subjected, 
or, in other words, it is a test for utider-burned cement. This, however is a fallac\- 

The specific gravity of carbonic anlivdiidi' .ind of w.iicr hdno -SS and roo 
respectively, it will Ix- readily seen th.il ( oniparat i\(|\- small proportions of these 
substancr-s, absorlx-d frf)m tin- atmosphere, are sunici<iit to reduc^e the gravitv of 
cement to a material extent. 

I 26 



r>r^^5i^E?V^?^^ SOME FALLACIES IN CEMENT TESTING. 

Rutlcr Ii.is shown that if (he absoi Ixd water and taihonic anliydiidc be expelled 
l)\ ii^nilinj^ the I'eineni, the specifir i*ra\ities of cements of \a^iou«^ makes become so 
neai h' itlentieal as to afford no indication of cjiiality. 

The conclusions reached 1)\ Uutler were: (i) That the specific gravity of cement 
is no indication whatever of |)ropei- calcination. (j) That the s|)ecific fjravity depends 
upon the aj^e of the cement and the op|)orlunities it has had of absorbinj^' water and 
carbonic anhydride from the air. 

These conclusions are tjuile in accord with the exjxiience and the o|)inion held by 
nnself for some time |)ast. 

In ic)o4 or i()05 I'. M. Me\'er fomid, as the icsult of some hundreds of tests on 
freshh burned clinker, that the hij^hest specific ifravity was obtained when the clinker 
was burned at a temperature of 1,290° to 1,370° C. 'J'his clinker j^ave cement which 
was ex])ansi\-e and unsound. 

.\s the burnini^ temj)erature was raised, the sjM'cific i^ravity w.'is decreased, but 
th(> clinker became sound. 

My own experience is that when taken freshly from the kiln, the specific j^ravity is 
practically the same whether the clinker be well burned or under burned, provided the 
carbonic anhydride has been all, or nearly afl, expeUed from the chalk. This is in 
accord with some results published by Redi^rave, who found the specific j^ravities of 
four samples, taken from one place in the kiln, to be as follows : — 

Specific Gravity. 

1. Yellow, slack burned clinker ... ... ... ... ... ... 316 

2. Good clinker ... ... ... ... ... ... ... ... 3"i7 

3. Very lightly burned, showing spots of lime ... ... ... ... 320 

4. Over-burned vitreous clinker ... ... ... ... ... ... 319 

The specific gravity of cement being merely a measure of the degree of aeration 
which the sample has received, and the finer particles being naturally more absorbent 
of water and carbonic anhydride than the coarser pieces, it follows that a finely ground 
cement, containing much Hour, will more rapidly have its original specific gravity 
reduced by aeration than will a coarsely ground sample, and would thus, falsely, aj)pear 
to be the more lightly burned of the two. 

It mav be thought that granting the specific gravity is merely a measure of the 
water and carbonic anhydride absorbed, and is no indication of calcination ; it might 
be advisable to retain the test with the object of detecting dangerous natural cements 
manufactured on the Continent, which cements are characterised by a high loss on 
ignition. Personally I am unable to agree with this for several reasons. Firstly, the 
direct method of estimating the loss on ignition is more accurate than a determination 
of specific gravity, which is an indirect method, and, moreover, a more difficult and 
uncertain operation. Secondly, an artificial cement, especially if finely ground, exposed 
to air or kept in a damp store for some time, may have its gravity reduced to a figure 
quite as low as that of many natural cements. Thirdly, no single test of this nature 
is sufficient to determine whether a sample is or is not a natural cement. The only 
certain guide is a chemical analysis, and having this data, the specific gravity becomes 
superfluous. 

STANDARD SAND. 

There is a somewhat general idea that tensile or crushing tests of cement with 
standard sand represent the best results of which the cement is capable. This is 
erroneous. .Sand tests do not give the highest results which can be got out of the 
cement, but give results which are standardised, and therefore comparable with those 
obtained by different operators. 

The standard sands emploved and specified in different countries vary in size to 
some extent, as shown in the following table : — 



TABLE D. 
Residue on Sieves, Per Cent. 



German sand 
French sand 
Austrian sand 
American sand 
English sand 



20^. 


30Z 


17-4 


100 


9i'o 


100 





— 





100 





lOO 



40^ 



127 



THE CONCRETE INSTITUTE. [CQNCBETE] 

These differences in size of grain doubtless have their effect upon the results 
obtained. Actual experiments indicated that the crushing resistance of concrete made 
from the same cement varies not only with the size, but also with the character of the 
aggregate. On comparing the results of the tests with standard Leighton Buzzard sand, 
all passing a sieve of 20 mesh but retained on a 30 mesh, and those with pit sand passed 
"through a 5-in. mesh only, an apparent anomaly is observed, as the apparently larger 
grained pit sand gives a less crushing resistance than the standard sand. This is not 
really anomalous, because although the pit sand was only passed through the 5-in. 
screen, it contained a considerable quantity of very fine stuff which would probably have 
passed a 5o=-mesh sieve. 

The results indicated that the crushing resistance of concrete made from the same 
cement varies not only with the size, but also with the character of the aggregate. 
On comparing the results of the tests with standard Leighton Buzzard sand, all passing 
a sieve of 20 mesh but retained on a 30 mesh, and those with pit sand passed through 
a i-in. mesh only, an apparent anomaly is observed, as the apparently larger grained 
pit sand gives a less crushing resistance than the standard sand. This is not really 
anomalous, because although the pit sand was only passed through the 5-in. screen, 
it contained a considerable quantity of very fine stuff which would probably have passed 
a 502-mesh sieve. 

The whole of the specimens were kept in damp air only until due for crushing. 

AUTOCLAVE TEST. 

This test, recently proposed by Mr. H. T. Force, in charge of testing materials on 
the Delaware, Lackawanna, and Western Railroad, of Scranton, Pa., is merely a revival 
of Dr. Erdmeyer's high-pressure steam test introduced in Germany about 1881, and 
rejected by German cement experts as being unreliable and misleading. In the words 
of Professor Gary, of the Royal Bureau of Material Testing, it is even less adapted to 
distinguish useless cements from useful cements than the usual methods of determining 
constancy of volume. According to Dr. Cushman, of Washington, the details of the 
test have been several times revised during the last twelve months, but the procedure 
is now as follows :— 

For each test three neat briquettes are made, and after twenty-four hours in a moist 
closet these are weighed and then placed in the autoclave, sufficient water being added 
to cover them. Pressure is then raised bv heating the apparatus by gas burners or 
other suitable means, the time taken to raise the pressure to 295 lb. per square inch 
being not more than one hour. 

The pressure is maintained at 20 atmospheres for a further period of one hour, at 
the end of which time the autoclave is slowly blown off, the briquettes removed (when 
their condition permits) and placed in the moist closet for one hour. They are then 
re-weighed and broken in the cement-testing machine in the usual manner. The 
tensile strength so obtained is compared with that of twenty-four-hour neat briquettes 
kept in moist air, and must show an increase of at least 25 per cent, over the latter. 
The autoclave briquettes must also develop a strength of at least 500 lb. per square 
inch, and the gain in weight must not be greater than i per cent. Expansion bars, 
I sq. in. in section and 6 in. long, are also made up and tested for expansion after 
twenty-four hours in the moist closet .and two hours in the autoclave. The expansion 
of these bars must not exceed one-half of i per cent. 

I hold that growth of strength by age is of less importance and is not such a 
critrrion of quality as is gencrall\- considered. Modern cements pre])ared froni j)urer 
clinker and much more finely ground than formerly attain a strength ai)proximating 
to the maximum much more quickly, and it is evident that a cement which attains, 
say, 'S of its maximum strength at short dates, has less margin for growth than one 
which only develofjes '5 of the maxinuim in the same time. 

The stipulated pressure to be mainlained in the autoclave (20 atmosj:)h(M-es) is 
needlessly high and serves no useful pui'|)ose. 

Quite recently the autoclave test has been subjected to critical examination, both 
in the United States rmd in Canada; and th(! conclusions arrived at are that a case 
for its adoption has not been made out. 

FREE LIME. 

No theory conn<<ted with Portland cement has obtained a stronger hold, or has 
attained such hoary antiquity, as the idea that unsoundness of cement is due to free 
128 



[^eS^jTeJ^nS^ so,!//-: FALLACIF^ IN CEMENT TESTING. 

linif l(H-kt(l up within llic p.irticlcs ol ihc i^iound m.ilcri.il. In l.i<l, lliis ihcoiN has 
been for so \on^ acccplcd lli.il lo qiicsiion ii in;i\ jjossibly he mk i with derision. 

The improvcmcnl in soiuuhuss, hroui^ht .ihoiit l)v the cxijomhc of rcnicnt to a 
(iain|) atinos|)h('r(', lends some appar(Mil support to the conlenlion that Urc lime is 
thereby slak«'d and rendered harmless; but it is rather dirikult to understand iiow lh<- 
small amount of moisture absoibed from the air penetrates the particles and slakes 
the free lime when the enormously i^reatei- tjuantily of water used in j^au^in^ the 
cement fails to touch it. b\!rlhermoi c, imsound cement stored for some time in air- 
tii^hl receptacles, in which i)resumably no slakinj^ of free lime can occur, becomes 
j)erfectly sound. 

Exposure of cement to air for a few days sometimes residls in an increase in the 
amount of expansion, as tested 1)\ the Le C'halelier method, and this increase is nearly 
always proj)ortionate to the amount of aeration underj^one- 7.r., the thinner the la\er 
in which the cement is laid out, the {greater th(^ increase of ex|)ansion. 

\\'(> know ver\' little 3'et of the properties of lime in a state of solid solution. It is 
stated to be crystalline and to hydrate slowly; but if the solid solution theory be correct, 
crwstalline free lime is present in considerable quantity in all Portland cements, 
whether sound or unsound, and it has not been satisfactorily explained why the lime 
hvdrates without expansion in one cement but docs so with destructive force in another. 

It is also well known that a low-!imed cement is often more unsound than a high- 
limed cement, which aj^ain is antai^onistic to the free lime theory. 

My own view is that unsoundness in cement is probably due to the presence of an 
abnormal silicate, perhaps dicalcium silicate, which is an unstable compound and 
slowlv disinteLjrates with an increase in volume. The phenomenon of " creepini^ 
clinker," known to cement makers, is an illustration of the disinte^^ration, with 
increased volume, of dicalcium silicate, which is formed when clinker contains an 
insuificiencv of lime ; and this or a similar compound is most likely to be found in 
unskilfully made cement in which the proportions of lime, silica, and alumina are not 
]:)resent in correct combining' weights, or when the temperature of burnini:^ is insuffi- 
ciently hii^h to induce the formation of those silicates and aluminates which constitute 
true Portland cement. 

DISCUSSION. 

Mr. D. B. Butler, Assoc. M.Iast.C.E., fully concurred that cement testing was a highly 
specialised skilled work. Aeration was not so necessary as it was some years ago; if cement 
would stand the British Standard Specification requirements as regards soundness, that was 
the rotary test, aeration was unnecessary. Absolute accuracy in the preparation of wire sieves, 
he believed, was almost impossible. The specific gravity test he considered practically of no 
worth. As regards the autoclave test, what was the good of subjecting cement to a high 
pressure of steam? The idea of testing cement for soundness, he thought, was to determine 
whether or not that cement would eventually expand or cause trouble in work. The boiling 
water test in niaie cases out of ten was unnecessarily severe. The conditions of the setting and 
hardening of cement, the different conditions between hot water and cold water were quite 
different ; and because a cement would expand in boiling water, it did not by any means follow 
that it was going to expand under other conditions. To enable a cement to pass the standard 
specification test, it had behoved manufacturers to greatly improve their methods of manufac- 
ture, and in that way indirectly it had immensely helped the British industry, but at the same 
time — it might be heresy to say so^ — he thought it was unnecessarily severe in the ordinary way. 
After all, the idea of a soundness test was one which would show them unsoundness, and not 
one which improved manufacture. The next point was free lime. Free lime in cement did 
not exist; he did not think it ever had. The cause of expansion of cement occasionally, which 
was much less frequent now than it used to be, was not free lime. Anyone who had tried to 
burn or to place lime at a higher temperature in juxtaposition with acid bases would find that 
it was impossible to prevent that lime from burning in places. His own theory as to the reason 
of expansion was that it was not free lime, but that it was a highly expansive lime compound 
of some kind, which very slowly hydrated, and expanded during hydration. He did not believe 
that free lime could exist in an ordinary "Portland cement. 

Mr. William G. Kirkaldy, Assoc. M.Inst. C.E., declared himself in favour of the Le 
Chatelier test, although some years ago he regarded it as too drastic. 

Mr. Percival M. Fraser, as an architect, remarked that the main object of the Paper 
seemed to be to decry all known tests. The autoclave test seemed highly fantastic, but they 
must remember that the Le Chatelier test was considered a freak test when it came m. In 

129 



THE COXCRETE INSTITUTE. tCQNCJ^lHd 

regard to the testing in general, he was afraid his brother architects were satisfied with the 
tes'ls that he was brought up on : filling a bottle full of cement at night, and if it did not either 
burst the bottle or act as a sort of small rattle next morning it was all right. He considered the 
crushing test should be developed and made a standard, as in time, he believed, it would replace 
the somewhat futile tensile test. In regard to the test sieve, he agreed that the expanded sieve 
was a verv immature method, and he suggested the substitution of a perforated sheet. 

Mr. W. a. Perkins, District Surveyor for Holbora, did not think there was anything 
in the Paper, with the exception of the boiling tests, and the question as to free lime, which 
would guide them as to the soundness of any cement that they might wish to use in their works. 
On the question of the sieves he agreed with all that had been said that evening. Some time 
ago thev heard a good deal of a little instrument which was termed a " flourometer," by 
means of which those iK)rtions of cement which were ground to an impalpable powder were 
blown away from the coarser particles, and collected in a special vessel. Had that particular 
instrument been dropped? 

If not, would not that be a better way of obtaining a perfectly fine cement, and so get 
something which was reliable on the score of fineness? He did not think there was much in 
the autoclave test, but the Le Chatelier method of testing cement he regarded as a good one. 
On the question of free lime, he thought they more often got free lime introduced into the 
cement on the works, either by the careless stirring of the cement in close proximity to a bin 
of lime, or they found it in the bricks or the tiles that were being used in conjunction with 
the cement. 

Mr. J. N. N. Sbi/lito urged that some time-limit should be fixed for the taking of 
samples after the cement had been delivered on the job. 

Mr. W. A. Short asked Mr. Gadd to give them some rough outline of the course he 
pursued in testing the excellent cement which his firm turned out. Perhaps he might favour 
them with what he would suggest as an ideal form of cement testing. With regard to the 
question of sieves, possibly the National Physical Laboratory might be able to help them. 

The President, in moving a vote of thanks to Mr. Gadd, said he should have liked to 
have seen, in regard to the tests, an analysis of the cement used, in order that they might, if 
possible, come to a definite conclusion as to the variation in the results. He had found a very 
good method for measuring and also for determining over large areas the variation in sieves 
was the use of the magic lantern. As the result of some experiments he made some years 
ago he found that if concrete were made simply with residues only, and kept in dry air, 
anything that would pass through a i6o sieve was absolutely useless. Briquettes made with a 
residue coarser than i6o were all blown, and that was due entirely to the gypsum. With 
reference to standard sand, he made his own from oolite or Portland stone, and he found that 
he got very much better results from sanid that would pass through a 20 sieve, and be retained 
in a 30 than he could get with the ordinary Leighton Ikizzard sand, and that was due entirely 
to the fact that all sand that came from Portland stone was extremely porous and crystalline, 
and that there was a locking action taking place between the cement and the stone. He got a 
very much more uniform result, especially in tension. He was pleased to see tlie high results 
Mr. Gadd got with an ordinary 4 to i concrete, where he had been using Kentish rock-stone. 
With a limestone, and especially the oolites, they would always get a very much greater 
strength in crushing resistance than they would with any of the smooth and the harder stones. 
Personally, he should like to see all neat cement tests done away with except as to soundness 
and setting time, so that they should rely entirely upon the 3 to i sands in tension and also in 
compression, and he thought that before long that would be adopted in this country, as was the 
case in Germun\'. 'J"he " flourometer " he considered was a very good thing for experimental 
puri)Oses, but if one had to use a " flourometer " to get all the flour out of a ton of cement they 
would have to wait a very long time, and when llie\- did get it it would be of very little value. 

MR. LAURENCE GADDS REPLY. 

Mr. (Jadd, in a( know Irdgiug the \oir ot thanks, rci)lic<l to several of the observations 
whifh harl been made in the course ol the discussion. As to Mr. Hutler's criticism on the 
aeration of samjdes, his i>oint was this, lli.ii for I he purijosc of making a setting lime test, 
aeration was not only unnecessary, biil il was misleading. AiTaling the small sample of 
cement ui^on which they were to make their test was subjecting that small sample to influences 
to which the bulk cement was not subjected. Whether c c-ment contained gypsum or not, the 
effect of water and GO^ respectively was ail the- same. Water wouici retard the setting time no 
matter whether there was g\i)sum present or not, and c arhonic anli\ <lii<h' would accelerate the 
setting time. If some <:entral authority c<Hild |)ro\i(h- ilicm willi standard sieves, which were 
standarcl, it would i>e a very great convenience, anc] it would also be a very useful thing, if 
they coulcj get an intern.it ional sand, to people who vvc-rc- sc-nding i cnienl out all over the 
130 



teScSS'^SK^ SOME FALLACIES IN CEMENT TESTING. 

world, llr ( amc across inan\ sptN iinriis of (linker wliicli were quilr brown, ( olit'i-t oloureilj in 
fact, due to tlu- reduction of iron salts, hut he did not find thai that clinker was any more 
unsound than Lhc <>rdinar>' (linker. Mr. iVrcival Fraser was the s|)eak<'r who gave him the 
greatest sluxk, when he said that the ohje'ct of his Paper api)eared lo he lo run down every 
test there was. That was not his object. The object of lh<* I'ajjer was to point out those parts 
of the t<"s( whifh, in his opinion, were faulty. He did not say do away with the tests, 
but if an\ jxirtion of the test was misleading or faulty in an\' wa\, lei them do away 
with the faulty i>art and improve it. He was further slux ke<l by the suggestion that 
he decried crushiing tests. lie was ver_\- sorrv if he gave Mr. Fraser that impression, because it 
was contrary to his view. He agreeti that if they mi.xed sulphuric acid with the cement they 
would liave a retardation of setting time just the same as if they added gypsum, but no acid 
got into the cement that he was experimenting with. Calcium sulphate in broken bricks or 
anything else in any quantity was about the worst thing they could mix with Portland cement. 
As to Mr. Shillito's suggestion, that was not a matter for him, as he did not represent the 
Standard Specification or the Sijccification Committee. With reference to Mr. Short's (juestion, 
he was Ixiund, like everybody else, by the Standard Specification. He made the tests according 
to the Standard Specification, but if Mr. Short asked him what tests did he rely upon for his 
ow-n information and his own judgment, he relied principally upon the crushing tests; and he 
formed his opinion without the aid either of specific gravitj' or aeration. Several times he 
had tried to do away, or to find the means of doing away, with wire sieves. There was no doubt 
that if gypsum were added to cement, and it was not finely ground and ecjually distributed 
all over the cement, they might get little particles or nodules of gypsum, and where those 
occurred undoubtedly there was the nucleus of expansion, but that would take place in the 
cold, and it did not need boiling to bring it out. He agreed with the President in his hope 
that some day all neat tests would be abolished, and that they should rely entirely upon sand 
tests. 



131 



NEW WORKS IS CONCRETE. 



ICQNCBETEJ 



NEW WORKS IN CONCRETE 

AT HOME AND ABROAD. 

Under this heading reliable information "Will be presented of neiv ivorks in course oj 
construction or comoleted, and the examples selected ivill be from all parts of the 'world. 
It is not the intention to describe these ivorks in detail, but rather to indicate their existence 
and illustrate their primarv features, at the most explaining the idea 'which se^'ved as a basis 
for the design. — ED. 



REINFORCED CONCRETE WATER TOWER NEAR BURTON-ON=TRENT. 

The water tower shown in our illustration has quite recently been erected entirely on 
the Coii^net svstem of reinforced concrete at Rolleston-on-Dove, near Burton-on-Trent, 
for Sir Oswald Moslev, Bart. This water tower is in connection with the water supply 
for the villai^e, the engineer for the work being Mr. John Frith, of Basloy, Derbyshire. 




View of Completed Structure. 
Reini oRf I'D CoNCKi TK Watkr Towkr, Burton-on-Trent. 



132 



fy, CONN TkMin lONAi: 
l/y I NdlNl ri^lNCi — , 



REINFORCIiI) CONCRETH WATER TOWER. 





1 he 


tank 1 


las ; 


capacity of 


hi-l 


1 ;iiul 


2.S ft. 


111 ( 


lianictcr. T 


tow ( 


•r is 


:;j II. 


Ihr 


inside of th 




Reinforced Concrete Water Tower, Burton-on-Trent. 



45,000 i^allons, and is in the sliajx' of a cvlindcr 15 ft. 
ic total iK'iLjlit from the j^round level to tlic top of the 
■ lowci' includes a fiisi ;ind second lloor, and lliere is a 

balcony on >.«'(()nd floor, as shown 
in the photo^iajjli. Access to the 
iip|)ei' llooi's is ^ivcn b\ means (jf 
a wooden staircase. 

The water is forced into ihe 
iaid< 1)\' means of piimj)s, the 
inlet and overflow pipes beinj^ 
fixed inside the tower. 

The work was carried out 
1)\ the Derbyshire and Notts 
("oi^net Contracting (.'0. (Messrs. 
Ivvans Bros.) of Alfrelon, and the 
worl-cini^ drawinj^s were ])re- 
|)ar(d by Messrs. Edmond CoitJ- 
nel, Ltd., of 20, Victoria .Street, 
Westminster, S.W. 

The reinforcement is com- 
posed of round bars of mild 
steel supj)lied by Messrs. The 
Whitehead Iron and Steel Co., 
Ltd., Tredegar, Mon. 

The tank was rendered on 
the inside with sand and cement 
and filled with water 14 days 
after the concreting operation 
was finished. A slight dampness 
l3 appeared at first at the junction 
of the wall in the bottom, but, 
as usual in reinforced concrete 
water tanks, these signs disap- 
peared after a few days. 



A REINFORCED CONCRETE 

BRIDGE AT WICKHAM 

MARKET, SUFFOLK. 

The bridge over the River Deben 
at Wickham Market, Suffolk, 
which was partially destroyed by 
the floods in August, 1912, has 
recently been replaced by a new 
reinforced concrete structure de- 
signed by Mr, Henry Miller, 
with Messrs. L. G. Mouchel and 



M.Inst.C.E. (County Surveyor), in conjunction 
Partners, Ltd., of 38, Victoria Street, S.W. 

The new bridge, which is constructed on the Hennebique system, has a span of 
48 ft. clear of the abutments, and an overall width of 28 ft., as against 36 ft. and 26 ft. in 
the old bridge. The old brick abutments were taken completely away and new abut- 
ments in reinforced concrete constructed, 6 No. 14 in. by 14 in. piles, and 35 No, 6 in. 
by 12 in. sheet piles were driven on each side of the stream, the existing brick culverts 
under the approaches and the wing walls being retained. 

The bridge is constructed in two spans, the central support consisting of 3 Xo. 
14 in. by 14 in. piles, with 14 in. by 6 in. diagonal bracings and 14 in. by 8 in. 
horizontal cross bracings as shown in cross-section. 

With regard to the reinforced concrete superstructure, the decking of the bridge 
is 7^ in. thick, the main beams being 10 in. bv 22 in. at 10 ft. centres, and the 



i.U 



NEW WORKS IN CONCRETE. 



lOQNCBETEJ 



secondary beams 6 in. by 14 in. at 4 ft. centres, with a reinforced concrete parapet and 
coping' as shown. The carriai^'eway is 20 ft. wide, paved with ffranite <=etts on ordinal y 
concrete, the thickness of the setts and concrete liUing at the crown of the road beini^ 
14 in. and at the curbs 10 in. Footpaths, which are carried on reinforced concrete 
corbels at 4 ft, centres and linished in i^ranoHthic, are provided on each side of the 
bridge 2 ft. 6 in. wide, giving a total width between the copings of 25 ft. 










.2 ^ 



o 



The new bridge, which has taken .iboiil six nuMilhs to construct, was tested last 
December, and aft;-rwards opened [o trallic in the presence of a larg(! representative 
comjjany. 

'Jhe contractors for the work wcrt Mcssis. IIoIIowmn' i^ioliiers (London), Ltd., 
Belvedere Road, Laiiibnli, S.I".. 

134 



J coN.^MJucriaNAi.i 
rvKNr.iNhi.uiNd --J 



REINFORCED CONCRETE GASHOLDER TANK. 



REINFORCED CONCRETE GASHOLDER TANK AT H AM BURG-FUHLSBUTTEL. 

Ml.SSKS. ClIKlMIAM AM) NlKl.Sl-N, d ( •. >! ). 11 1 1. 1^. 1, , ll.lX.' 1 . (CM 1 1> fOIlsl lUClcd t Ik • 



louiul ition ;.iul l.niU l.>r a lar^o ^ashoUlr, in r.inlnicvd o.ncnK-, for the (.as Li^hUn^ 
Com.nittrc of I'uhlshullrl. As th<' d.-plh «.l wal.r is S nicli.s the containing nn^ is 
suhjrclcd to a hmslin- pressure due to tliat h.ad of wat. r, whilst th<- n^id connections 




at the base introduce considerable fixing moments. For the computation therefore, 
the stresses in the rini^ due to these two causes are the deternTining factors 1 his inNOlxes 
a special method of computation, the triangular area which represents the h>drostatic 
pressure being divided in such a way that at every point the deformation due to the nng 
stress is equal to that due to the fixing moment. 

135 



SEW WORKS IN CONCRETE. 



fCQNCRETEl 



The internal diameter of the containing tank is 57-4 metres, the thickness of the 




Iiilciicr View. 

J<,.,,MO.'.hl. CoNC.<l/iK GASnol.l>ER-TANK AT 1 I AM Hf Kr.-lM ' i 1 l.Slir 1 1 KI.. 

the gasholder a plat. 20 r.n. lliick, r.-infon.d wi.h wi.v nuslus, slrcngthened by 16 
rl^^gs nclar to th' ou.-r c.ig.-. Tlw has. of ih. lank has a .uax.nuun thickness ol 



I metre, dimiiiisliing outwards and inwards 



T.' 



FURTHER CONCRETE WORK AT TALBOT S INCH. KILKENNY 

)SF Of the latest a<hli,ioM. .0 th- n>anv laiiMin^s rnrU.\ in -W.nget ^ oeks n 
''iho's nch, for th. Kilk..>nv W oo.lwork.rs, und.r .h. aus,.,e.s of the K.-ht 



136 



foT cTON> rwwn ionaJ 



Rh:iNF()RCIiD CONCRETE GASHOLDER TANK. 





»37 



NEW WORKS IN CONCRETE. 



[CONCBETEJ 




138 



^ t-N(ilNt.I-RlNti — , 



CONCRliTlC liLOCK WATER RliSERVOlR, 



I lonour.ihlr l'.ll«n (■(Uintcss Dow.i-ci ol D.s.n i, Is Ik !<• show ii. The w.ilc r t()\\<T canics 
llic "o<)() i^.illon l.ink for the spiiiiklci insi;ill;irKm in the w nodw oik* rs" factorx, tho 
basc'of same \n\\v^ i^ It. 1)\ M I'l-, \^ill> •' <«'>•'' Ixi.^l" (iiuIiidinL^ lank of i) fl.) of jusl 

<»\('r \o W. , 1 1 • I 

i'lu' " W'iii'Mi " Itlncks used in ihc cicrlion air doiiMr and sini^lr Hue blocks, which 



,^ 



T 







Concrete Block Water Reservoir, Talbot's Inch, Kilkenny. 

are reinforced at the inner corners with il in. bars, the inner space being filled in with 
rough concrete mixed 7 to i. 

At the top of the tower for about 23 in. the girders are placed supporting the tank, 
all of which .are encased in concrete. 

The blocks were made by Messrs. The (\)ncrete Hlock Co., of Talbot's Inch, and 
the whole of the work designed and carrit d out under the supervision of Mr. F. \\ . 
Kiddie, of Talbot's Inch. 



1 ^0 



MEMORANDA. 



E CT^CRETEl 




MEMORANDA. 






Memoranda and Neivs Items are presented under this heading, with occasional editorial 
comment. Authentic netos 'will be ivelcome. — ED. 



International Association for Testing Materials.— A meeting of the British 
Section of the Intcrnaiional Testing Association was held at the offices of the Iron and 
Steel Institute, zS, X'ictoria Street, London, S.W., on Thursday, December i8th, 1913, 
at 4 p.m. 

The chair was taken bv Dr. \V. C. Unwin, and there were also present : Dr. H. 
Borns; .Mr. S. M. Dixon'; Mr. F. W. Harbord ; Mr. D. Heap; Colonel Herbert 
Hughes, C.B. ; Mr. \V. G. Kirkaldy ; Mr. R. Lessing ; Mr. G. C. Lloyd; Mr. J. T. 
Milton; Mr. H. Moore; Mr. L. S. Robertson; Dr. F. Rogers; Dr. Walter Rosenhain ; 
Mr. E. H. Saniter; Mr. J. Cruickshank Smith; Mr. F. Tomlinson ; Mr. Howard 
C. Wolfe. Letters of regret at their inability to be present were received from 
Sir H. F. Donaldson, K.C\B., Sir Robert Hadfield, F.R.S., Mr. E. O. Sachs, and 
others. 

The draft scheme of organisation, drawn u|) by the provisional Committee of 
Management, was submitted to the meeting, and approved, subject to certain alterations. 

The subject of the mode of dealing with such annual subventions from manu- 
facturing firms, scientific and technical societies, institutions, and i)ublic bodies, as 
might from time to time be made, and of the question of representation of such bodies 
within the British Section, was referred to the Committee of Management. 

On the motion of 
Mr. J. T. Milton, a 
cordial vote of thanks 
w a s unanimously 
passed to Dr. Unv/in 
for jjresiding. 

The Society of 
Engineers (Incor- 
porated) Status 
Prize. The Council 
(jf tlic Society 01 En- 
gmff-rs (Incorpor- 
ated) may award in 
1914 a premium of 
Dooks or instrumcnls 
to the value of £\() 
IDS. for an approvi-d 
essay on " The Statu-- 
of the Engineering 
Profession." T h c 
Council reserve the 
right to withhold 
the premium if llw 
essavs received are 




I<KIMOI«(.IH CoN< KK 1 K I'1-.N(K PuS I S Al DiNAS WaV, H A\KK lORinVK^T. 



140 



i, (.ON.vrPUCTlONAI. 
A LN(ilNt-l-kIN(i — , 



MEMORANDA 




Reinforced Concrete Fence Posts, Dinas W'av, HAVLKhoKUWi.sx. 



iidi nf ;i ^uHl^i»•llI sl.iiul.iid ol niciil. The (oiupct ii ion is open lo .ill, hut, Iv f(>i'- 
cnli riiii^, ;i|)i)lii;il iiMi Icti (l( l.iilrd |):irl icul.irs should he iiiadf lo the Sccrctarv , 17. 
X'irioii.i Slictl, W'csimiiisit T. The last date for i(C(i\in<^ css.'iNs is Ma\ 3<)lii, i:(i4- 

Reinforced Con 
Crete Fence Posts 
for Dinas Way, 
Ha verfo rdwes t. 
\\\ reproduce ilere- 
\\ i I h t w o photo- 
i^iajjhs of sonic rt'lii- 
forct'd concrete work 
carried out in eon- 
n e c t i o n with the 
above new r o a d s. 
'J'his new route lo 
Fishj^uard has re- 
cently been coni|)le- 
led by the Pembroke- 
shire Horoui>h Coun- 
cil. For a consider- 
able distance it skirts 
aloni^ the hii^h cliffs 
overlookini;' F i s h - 
guard Harbour, and 
then turns to the 
right overland. It is 
2,600 ft. in length, 
with a carriageway 
of 20 ft. and a foot- 
path of 4 ft. The boundary fences on the land side consist of reinforced concrete posts 
and wire strands. The engineer for this roadway was Mr. Arthur Thomas, of Haver- 
fordwest, and the contractors were Messrs. Topham, Jones and Railton, of Westminster, 
London. The whole of the fence posts were manufactured and erected by the 
Reinforced Concrete F'ence Posts, Ltd., of Broadway House, Westminster. 

Reinforced Concrete Boat Ways, Rockhaven Harbour, N.D.— In a short articl- 
in the Eugiticcriiig Xeius Mr. S. R. Morrow gives some particulars of some reinforced 
concrete boatways constructed by the United States Government at Rockhaven Harbour, 
N.D. He states that the U.S. Engineer Office of Kansas City, Mo., has departed 
from the old practice of building such structures entirely of wood. Rockhaven Harbour 
is located on the west bank of the Missouri River about four miles above Mandan, X.D.. 
and is the site of the repair plant for the fleet of Government vessels used in the control 
of the river. The new ways there, shown in the accompanying illustration, are of 
reinforced concrete with a timber " butter board " on top for the sliding plane. 

There are ten w.ays, each 270 ft. long, the lower 130 ft. being on a 1 to 7^ slope 
and the upper 140 ft. level. They are spaced 14 ft. centre to centre, and are supported 
on concrete columns 10 ft. centre to centre. The largest vessel for which they were 
designed is a steel-hulled boat 155 ft. long and 24 ft. beam. 

The columns, with the exception of those at ends and top of slope, are 12 in." square 
and are placed to an average depth of 6 ft. in the ground. Where a good foundation 
was not struck at this depth an 8 in. post-hole auger was used in boring a hole to solid 
foundation. These holes were filled with concrete and were assumed to act as piling. 
Witli the exception of a few of the columns at the foot of the slope a good foundation 
of blue shale was generally struck at a depth of b ft. The columns were flared at 
bottom to 20 in. square, thereby increasing the bearing surface. As the earth had no 
tendencv to cave, no forming was used underground excepting with the columns at 
water's edge, which were 4 ft. square and were built in the edge of a sand bar. 

Each column was reinforced with four f in. square twisted bars which were bent 
over and projected 2 ft. 2 in. into the beams. The aggregate used in concrete was a 
native gravel which contained sufficient sand and some dirt. On account of this dirt 
rich concrete was used, the mixture being i : 4. The water for concrete was pumped 



F2 



M' 



CDNCELTEZ 



CONSTRUCTIQNAI:^ 




PILE DRIVING PLANT 




WE MAKE PILE DRIVING PLANTS SUITABLE FOR THE 
LIGHTEST TIMBER SHEETING OR THE HEAVIEST FERRO- 
CONCRETE PILE, FOR STEAM, AIR, OR HAND POWER 

STEEL SHEET PILING 

*' Universal Joist" - 43 lbs. per super, ft. 
*' Simplex" - - 27 lbs. 

''Simplex" - 22 lbs. 



»» >» 



»> »> 



We buy the Piling Lack at tfie end ol the job, making the cost to the user approximately 
1/10, 1/4, & 1/- per su[)cr. foot respectively 



CATALOGUES AND FIRM QUOTATIONS ON APPLICATION 

THE BRITISH STEEL PILING CO. 

DOCK HOUSE, BILLITER ST., LONDON, E.C. 

Telephonr ; 5463 Avcnur. 



Tclciframs " I MmKdoii, " I ondon. 



142 



r J. CONMPDC-I lONALl 
(.< V 1 M(.lNKl-klNt. — ^^1 



MEMORANDA 



tliitillx Ironi ilif ii\(i lo h.intis ;ii mi\iiiL; pl.illoim l)\ inc.ms (if sin.ill ijliini^cr |)iim|, 
;iii(l hoisi hoilci . All concrclc w.is mixed l)\ ii.ind .ind disii il)ul( d in h.inows. 

I'hc l)»;iius or \\;i\s propci-, which ;iic i .• I)\ 14 in., wci'c stalled .iftcr .dl t'olunins 
w ( I < roniplclcd. The forms for tlicsc were m;i(lc in iwo sides .ind bottom. One set 
ol -ides ;ind two sets oj bottoms Were m.lde foi" (()m|)lete w;i\, J70 ft. Tile bottoms 
w ( r< su|)|)orted b\ il;im|)s on the colunnis. The sides w<Te ;dso supported b\ these 
clamps. Ilini^ed cl.im|)s were plared around the whole form, thus transferring part of 
the load Irom bottom to sides. The beams were allowed to set 24 hours with side- 
forms in place, and Irom 4S to ()(> hours with bottom forms in place. It took 
approximateh 11 hours to concrete one beam jyo ft. lom.^. 

Ihe beams were reinfoi'ced with two bent-up rods and two sliai^ht rods 2 in. from 
bottom. .\11 rods wore ^ in. square twisted steel. At lii'st no |)rovision was made for 
t(Mnpt'ralure stresses, l)ut a lem|)erature cracU appeared at the top of the slope in the 
first beam placed. This was jjartially overcome in succeedinj^ beams 1)\ |)lacim4 extra 
reinforcement in lo|)s of beams. 

The " l)utter boards " are 3 l)\ 12 in. by 20 ft. I'lr sticks sui)p()rted b\ 3 b\ 12 in, bv 
12 in, fir blocks, s])ace(.l 3 ft. 4 in. c. to c. Roth blocks and "butter boards" are 



•I 




Reinforckd Concrete Boat Ways, Rockhaven Harbour, U.S..\ 



anchored to the concrete by means of f by 11 in. machine bolts imbedded 7 in. in the 
concrete. 

Major Herbert Deakyne, Corps of Engineers, U.S..\., is the district officer for the 
Missouri River and tributaries. Fred \\ . Honens, Assistant Engineer, was in general 
charge of the work on the upper Missouri River, and Mr. Morrow was in local charge 
of the cotistruction of the wa\s. 

Concrete for Oil Tanks. — Experiments have been made to determine the avail- 
ability of concrete for oil storage tanks, and it was found that the material w-as entirely 
suited for the purpose. Accordingly, a number of them have been built at El Paso, 
Texas, by one of the railroad comj)anies of that stction which is engaged in extensively 
handling oil from the fields of that State. Up to this time it was generally agreed that 
the presence of oil had some serious effect on the concrete, but if this is true it was 
not shown by the ex]Kriments. — Concrete Age. 

1+3 



MEMORANDA. 



ICDNCBETEl 



Roof Construction on Concrete Building.- Whvlhcr the structural part shall be 
flat, and then covered wilh cinders lo ,<4ivc a proper pilch for drainage, or whether 
the structural part, including the ct'ilin_<j;, shall be j)itched and the fill avoided, is a point 
which niav be discussed to advanta^^e by eni>ineers, in the opinion of Mr. L. C. Wason^ 
President of the Aberthaw Construction (^o., Boston, in a paper read before the Boston 
Society of Civil Eni^ineers. 

In construction the most serious objection to the first method is based on the lajjse 
of time between the casting of the roof and the placing of the waterproof cover of tar 
and felt over the cinder fill. This usually i)ermits a quantity of rain to collect in the 
cinder on top of the roof slab, which, while not absolutely watertight, will still hold 
a considerable quantity of water. In some cases holes have to be drilled through the 
ceiling to drain this slab. In one building water from this source dripped from the 
ceiling five months after the roof had been waterproofed. In another case there was 
some dripping even after two years. 

CATALOGUES. 

Fred Braby & Co., Ltd. — A new handbook has just been issued by this 
companv, and it has been specially compiled for the use of architects and engineers. 
Illustrations are given of various buildings where the company's products have been 
used. The various tables as to weights, measures, currency, and calculations are a 
special feature of the book. The book will be forwarded on application to the company, 
at their offices, Petershill Road, Glasgow, or no, Cannon Street, E.C. 

CONTRACTS. 

Bell's United Asbestos Co., Ltd., Southwark Street, S.E.- — We are informed 
bv Messrs. Bell that a notification has been issued by the War Office that this company's 
tender has been accepted for the supply, during the three years 19 14, 1915, and 19 16, 
of asbestos-cement (" Poilite ") roofing slates, wall and ceiling sheets, etc., made at the 
companv's " Poilite " factory near London. 

CHANGE OF ADDRESS. 

Messrs. Geo. Sands and Son, Ltd., engineers and contractors, inform us that 
their London office has been removed from 37, Strand, W.C., to 31, Old Queen Street, 
\\ estminster, S.W. ^>lephone : X'ictoria 7854. 



EDITORIAL MEMOS. 

CONTRIBUTIONS.— Ori(^inal contributions and 
illustrations are specially invited from enfiineers, 
architects, surveyors, chemists, and others engafjed 
in practical or research work. MSS. should be written 
on one side of the paper only, giving; full name and 
address of the author. 

The copyrifjht of any matter accepted for pub- 
lication is vested solely in the proprietors of the 
journal to be used in any form they think fit. unless 
there be a special arranf^ement. 

MSS. and drawinfis or photof^raphs are sent in at 
the author's risk. Kvory effort v,ill, however, he 
made to return unsuitable communications. 



PUBLISHER'S NOTICES. 

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Monthly. For Advertisement Rates apply to Pub- 
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by 12th of month prior to subsequent issue, for 
Wants column by 18th. 



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General Offices : 
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For Canada: The Toronto News Company and the Montreal News Company. 



'4+ 



/yy 



CONCRETE 

AND 

CONSTRUCTIONAL ENGINEERING 



Volume IX. No. 3. London, March, 1914. 

EDITORIAL NOTES. 



THE PANAMA CANAL. 

A SERIES of articles dealing- with some of the constructional features of the 
greatest of the world's great works in which concrete has played such an 
important part — viz., the Panama Canal — appeared in our Journal in 191 1. 

In this issue and a subsequent number we present two further articles, 
descriptive of other concrete and reinforced concrete work on the canal. 
Although the canal is not yet open for traffic, for all practical purposes the 
junction between the two great oceans has been formed, and it can only be a 
matter of months until regular traffic commences, and, as Mr. Leigh mentions 
in his article this month, " it is not unlikely that the canal will be in fit condition 
for trial navig^ation throug-hout its entire length within a few weeks after these 
words are in type." 

Any examination of the plans or photographs of this gigantic undertaking 
must vividly impress the observer of the enormous role played by concrete 
and by" Portland cement, more particularly in the construction of the immense 
locks whereby the difference of level, amounting to about 80 ft,, is overcome. 
Rarely has Portland cement been applied with greater care. Everything that 
forethought and science could devise has been done to enable the material to 
be applied to the best advantage under the difficult circumstances of locality 
and climate. 

That the Portland cement used was of American origin is only a matter 
of course ; m fact, the undertaking was American in every sense of the word, 
and preferential use was made of national materials, even where there may have 
been some slight difference of price against the purchaser when the home 
product was compared with ihat of other countries. Would that we in this 
country were as commercially patriotic as the American nation always proves 
itself to be, And then we would not find large contracts going abroad on mere 
fractional differences of price, and irrespective of the national aspects of all 
home undertakings and of the difficulties of supervision. 

At home, in our Colonies, and e\ en in such spheres of influence as Egypt, 
there is all too great a tendency to ignore the national and economic aspects 
of placing orders at home, and some of our Colonies are notorious for this 
failing. 

B 145 



FIRE-RESISTANCE IN FACTORY CONSTRUCTION. [CQNCBET E] 



FIRE-RESISTANCE IN FACTORY CONSTRUCTION. 

Ax ocellent paper has recenll} been read before the Concrete Institute on 
" Factory Construction," the lecturer being- Mr. Percival M. Fraser, 
A.R.I.E.A. 

It would lead us too far to deal with the whole of the paper in this editorial, 
but we take one section entitled " The Fire-resisting Properties of Reinforced 
Concrete," as it claims special attention. We concur entirely with what Mr. 
Fraser indicates, that hrc" damage cannot be properly made g'ood with insurance 
money where honest owners are concerned, having" regard to the dislocation of 
business and its effect on the output of the firm, which, as a matter of fact, 
may never properly be recovered. Again, office documents cannot be replaced, 
skilled workmen thrown out of employment go elsew'here, and there is always 
the risk that a fire w^ill be accompanied by loss of life. 

Gi\ en a really well-considered design for reinforced concrete construction 
and the careful selection of suitable materials, nothing better can be utilised 
in factory construction than reinforced concrete from the fire point of view. 

Mr. Fraser praises the rules of the fire insurance companies in the matter 
of reinforced concrete, and these rules were originally devised by a disting-uished 
fire insurance surveyor, the late Mr. James Sheppard, who associated himself 
most actively with the tests with constructional materials undertaken by the 
British Fire Prevention Committee, and his influence generally upon the 
constructional rules of the insurance companies of the last 15 years w^as of the 
utmost importance. These rules have been excellent and have done immeasur- 
able gc^-od, and in presenting Mr. Fraser's paper we have made a point of giving 
these rules in full. 

If all reinforced concrete construction, even where it does not come under 
insurance tariff rates, were constructed to these particular rules no great harm 
could be done, and, as Mr. Fraser says, the absence of irritating detail is 
particular]}- welcome, and it should be an object lesson to the London County 
Council and the Local Government Board that these practical rules could be 
devised ad hoc some ten years back and do great service to the community, 
whilst the wise heads of these two authorities and the various professional 
societies concerned have been for some five years debating over details. 

Our own \iew is that from the fire aspect it might have been well to exclude 
granite and granite chippings from the insurance specification, but obviously all 
such rules lend themselves to improvement, and when the next edition appears 
it might be well if some slight change were made in this direction. 

STANDARD METHOD OF MEASUREMENT FOR REINFORCED CONCRETE. 

I.\ this issue we publish ihc draft rc})()rt of the joint Committee of Representa- 
tives from \h'i Ouaiilit)' .Surveyors' Association, the Quantity Surveyor 
members of the Concrclc Institute, and the Reinforced Concrete Piactice 
Standing- Committee of the. Concrete Institute on a ^Standard Method of 
Measurement f(jr Reinforced Concrete; and we welcome this as an attempt 
to deal with a jnosl important matter which, up to the present, has been 
quite neglected, 'i'here is every mtcd to standardise some method of measure- 
ment, as the material has not been in g-cneral use for very many years, and, in 

146 



^'S^wSK'iNo^] STANDARD METHOD OF MEASUREMENT. 



fact, lluMC :\vc py()\):\\)\\ niany (Jiumtily Siir\cyc)rs who ha\(' never |)rt'pare(l 
hills ioi' iciiil()i(H'(l coiuictc woik, and in coiiscfpicncc lhc\ would he aj)t to 
j)i'o(H't'd in such a niannci' that Iriction would arise with the contract inj^' 
cui^incci in llu- pioc c ss ol sclllcnicnt, and l)y the adoption ol a standard 
nu'lhod this could be ,i\oided. 

We do led, however, that the method should he agreed lo hy th( London 
Master Builders' Association, and, in fact, a mandatory report issued under 
tlie present cMrcumstanc^es would, in our opinion, he a mistake, and a recom- 
mcndaloi) one would he preferable. The (juestion as to whether the Concrete 
Institute rej)resents jirofessional eng-jneers or conlractini^- engineers is cjuite 
oul of place, as the standard method sug-^ested should be a fair one and involve 
the minimum amount of labour, consistent with a satisfactory result, for all 
parties concerned. The question of piles and pile-dri\ in^- should n-iost cer- 
tainly be dealt willi l)y the committee, as this cannot be considered to come 
under the headinj^- of pillars. Also, why should not concrete pipes and other 
special features of this nature be included in order to cover every possible 
form of concrete work? Several interesting- points were raised in the discussion^ 
which we reprint m conjunction with the report, one of which was the question 
of taking- out the centering for foundations in units of a square. Whv should 
this not be billed in square yards, as the square foot is too small? The same 
might be applied to that for stairs, landing-s, and small floor slabs; and, in fact, 
to make it universal, this unit could be employed for all floor slabs, roofs, and 
walls. With regard to the term to be adopted for the centering or shuttering 
we consider the expression '' False Work " would meet the requirements 
and apply to all timbering, whether in the form of plain shuttering or temporary 
props. 

We hope that these points will be considered by the committee before the 
report is adopted and circulated. 

CONCRETE COTTAGE COMPETITION. 

^^'E have received various questions from would-be competitors in respect of the 
above competition, and ue are issuing a printed slip to each competitor who has 
applied direct to the office of this journal for the Competition Conditions, setting 
out the questions we have received and the answers that have been given. 
Clause 3. — Quite a number of questions have reached us regarding this clause. 
Various competitors have asked whether — 

(a) Each cottage is to have a frontage of 65 ft. or whether a series of six 

cottages will have a frontage of 65 ft. 
(h) Is it oi)tional to treat the six cottages as all in one block? 

Answer. — (a) There are six plots adjoining one another, each plot is 
taken at an area of 65 ft. frontage by 200 ft. depth, or, in other words, 
65 ft. frontage for each cottage or 130 ft. per pair of cottages. 

{b) It is not optional to treat the six cottages in one block. The 
competition is for suitable detached or semi-detached cottages, and at 
the most one pair of cottages could share a boundary line. 
Clause 5b. — Is it necessary for cottages to have both a front and back entrance? 

Answer. — It is not necessary for the cottages to have a front and back 
entrance, but whether only a front entrance be given or both, the 

B2 147 



CONCRETE COTTAGE COMPETITION. [0GJNQ3ETE ) 

entrance must in cither case be an indirect entrance whether it be to 
the livini^ room or to the kitchen. In other words, no direct entrance 
to any living room is permitted. 
Clause io. — (a) Must beds for the inmates be shown as separate single beds, or are 
ordinary double beds 6 ft. by 4 ft. 6 in. allowable? 

{h) Beds 6 ft. by 2 ft. 9 in. are given for adults and 5 ft. 6 in. by 2 ft. 6 in. for 
each child. Would it not be better that the dimensions be 6 ft. 6 in. by 
4 ft. 6 in. for adults, and 6 ft. by 4 ft. for children? 

Answer. — (a) Single beds must be shown, not double beds. 
(b) The sizes for the beds must be strictly adhered to. 
Clause 14. — Will a copy of the cubing figures satisfy the requirements for page 5 of 
descriptive specification ? 

Ans-wer. — A statement must be given by the competitor, beyond the 

simple cubing figures, as to how he himself has arrived at the cost, 

data, measurements, etc. 

Prices of Materlals and Cartage. — A number of competitors have asked whether a 

schedule of prices is issued as to the cost of materials, such as cement, sand, gravel, 

etc., and the cost of cartage. 

Answer. — It is not intended to issue a schedule of prices; it is left to 
competitors to use their own discretion in this respect. 



148 



J, tTONMi?i)c-naNAi; 

*V KNC.lNKl-RlNt. --. 



CONCRHTli: MASONRY IN THE PANAMA CANAL 




CONCRETE MASONRY 

IN THE 

PANAMA CANAL. 

I. 



By JOHN GEO. LEIGH. 

In 1911 this journal published a series of articles on the Panama Canal, but since the 
publication of those articles, much additional concrete -work has been carried out, and ive 
are therefore publishing tivo further articles on this great 'work,— ED. 



For iIk' expeditious completion and relatively economical constriution of the 
Panama Canal, the people of the United States are indebted in no small 
measure to a judg-ment delivered by President Roosevelt on February 19th, 
1906. Durino- the years which had elapsed since Congress authorised the 
acquisition of the rights and property of the second French Canal Company 
there had developed in the United States a strong movement in favour of the 
completion of the enterprise as a highway at sea level. With a view to closing 
this unwelcome controversy and so enable the workers on the Canal to pursue 
their operations and studies to indubitably useful and well-defined ends, the 
President convened a Board of Consulting Engineers, consisting of nine 
Americans, a high ofHcial of the wSuez Canal, and four experts nominated by the 
British, French, German and Netherlands Governments, to consider and report 
upon the various plans proposed to and by the then existing Canal Commission. 
This Board, as arranged, met at Washington, subsequently proceeded to the 
Isthmus, and in due course presented to the Commission majority and minority 
reports. These, in turn, were considered by the Commission, with the result that 
there were found in favour of a sea-level cr.nal a majority — eight in number, in- 
cluding the five foreign members — of the Board of Consulting Engineers and 
one member of the Canal Commission ; while five of the eight American members 
of the Board and a corresponding number of the members of the Canal Com- 
mission, together with the latter's chief engineer and Mr. Taft, then Secretary 
of War, strongly supported the construction of a canal with locks. It was 
after careful study of the various papers embodying these divergent views and 
exhaustive consideration of the whole subject that President Roosevelt, on the 
date mentioned, transmitted to Congress a recommendation that the Canal should 
be built on substantially the plan outlined by the majority of his .American 
advisers. 

There can to-day be no question as to the wisdom and foresight shown by 
President Roosevelt on this occasion. As he pointed out in his Message to 
Congress, there appeared every likelihood that a high level canal with locks 
would not cost more than half as much and might be built In half the time, 
that the risk connected with its construction would be less, that for large ships 
the transit would be more rapid, and that, taking all the circumstances Into 

1+9 



JOHN GEO. LEIGH. tPQINCkii:! jlj 

account, the victual cost of maintenance would be less. Concerning- the 

prophecies of disaster in which the majority of the Board of Consulting- 
Eng-ineers had indulged, he said little, contenting- himself with the remark that 
they appeared to be vitiated by failure to pay proper heed to the lessons taught 
by the construction and operation of the Sault Ste. Marie Canal, the great 
traffic canal of the Xcw World, which, although closed to navigation during 
the winter months, carries annually three times the traffic of the sea-level Suez 
Canal. He might have added, in the same connection, that insufficient regard 
had been devoted to the merits as constructional materials of concrete and 
reinforced concrete. 

EXPERT ERRORS. 

Speaking- g-enerally, it may be said that work on the Isthmus has been 
divided into two parts — destructive and constructive, and that it is upon 
completion of the first, and not the second, that depends the date when the 
great highway will be available for the use of the commerce and navies of the 
world. \\>11 within, and frequently considerably in advance of, the estimates of 
time required lor their completion, the locks and other massive structures, 
together with the wonderful installations of operating machinery hidden in 
their walls, are virtually ready for service. That the same cannot be said of 
the highway as a whole is due to miscalculations of possible difFiculties and 
dangers not less remaikable than those to which reference has been made. 

The amount of excavation required to complete a navigable channel across 
the Isthmus has greatly exceeded expert anticipations. The minority report 
of the Board of Consulting Engineers in 1906 estimated the total excavation 
necessary for a canal with a summit level of 85 ft. at 95,955,000 cub. yards, 
of which 53,765,000 cub. yards w'ould be taken from the Culebra Cut; and the 
majorit)- report of the same Board held that for a sea-level canal with a depth 
of 40 fi. the corresponding requirements would be 231,026,477 cub. yards and 
109,891,710 cub. yards. To show how deceptive were these estimates it is 
sufficient to note that at the close of last year the material already removed 
from the Cut, or awaiting- dredging, was double the amount originally estimated 
for the entire Canal and 22,000,000 cub. yards greater than the revised and 
more careful estimate of 1908. This increase has been due partially to the 
widening of the bottom of the channel in the Culebra section from 200 ft. to 
300 ft. and to other enlargements of the original plan. Primarily, however, 
it is the rcsull of tlic additional excavation of over 25,000,000 cub. yards 
consequent upon the development of slides and breaks in the banks of the Canal 
prism in the Culebra Cut. To meet the c()ntingen(>y of such cavings-in, the 
international experts in 1906 made wliat llie)' no doubt considered the generous 
allowance of 500,000 cub. \ards! I I.'i|)|)il\', at the moment of writing, the Cut 
has bc('i) .'ilmost wholly cleared, .'ind there a])])('ars every reason to believe that 
the slides have r^eached ihe .-mglc of i-cjjosc .tnd will, hereafter, give little 
trouble. This being so, it is not unlikely that llic Canal will be in fit condition 
for trial navigation ihroughoul its cnlirc hnglli within a few weeks after these 
words ar(; in 1\pe. 

Under these cin unistaiKcs, il seems oppoitune to recall the series of 
articles devoted to features of consl lucl ion.'il woi'k likeh to j)r()\e of special 

150 



l/v-Sa.Ty.',r^-| COSCRHTli MASONRY IN THE PANAMA CANAL. 




.'^surasftaif 




I ;i 



JOHN GEO. LEIGH. [CQNCRETEJ 

interest to readers of this journal which it was my privilege to contribute to 
the pages of the latter some three years ago.^ All the more important 
structures and installations of operating machinery to which attention was 
devoted in these articles have been completed, with results so satisfactory that 
there has been no hesitation in any quarter in commending the judgment of 
those to whose advocacy of concrete as a building material may be ascribed 
much of the success and economy of this side of canal construction. Referring 
to the locks, it may i)e noted that, at Gatun, owing to the greater depth of the 
foundations deemed desirable for the approach walls, and at Pedro Miguel and 
Miraflores, for various reasons, the estimates of concrete required have been 
subjected to the following revisions : — 

1910. 1912. 

Cub. yds. Cub. yds. 

Gatun Locks 2,000,000 2,050,000 

Pedro Miguel , 837,400 890,750 

Miraflores 1,362,000 1,412,736 

The actual amounts placed in the several locks and auxiliary works up to 
January ist of this year were : — 

Cub. yds. 

Gatun locks 2,068,089 

Gatun spillway 231,410 

Hydro-electric station ... ... ... ... ... 7j'^^7 

Gatun control house, ducts, etc. ... ... ... 2,993 

Pedro Miguel locks ... ... ... ... ... , 923,438 

Miraflores locks ... ... ... ... ... '1,500,525 

Miraflores spillway ... ... ... ... ... 79,004 

Pedro Miguel-Miraflores duct line ... ... ... 6,193 

Xot the least remarkable circumstance associated with the building of the 
locks has been the expedition with which the work has been accomplished. 
The placing of concrete began at Gatun on .August 24th, 1909; at Pedro Miguel 
on September ist of the same year, and at Miraflores, with the exception of 
ro2 cub. yards laid in July and August, 1909, and 500 cub. yards placed during 
February to May following, in June, 1910. Yet all the mass masonry at Gatun 
locks — the largest concrete structure in the world — as w^ell as at Miraflores was 
completed before llu (^nd of .May, 191 3, while that at I'edro Miguel was finished 
several months earlier. Subsequent work, for which, generally speaking, only 
portable mixers were requisitioned, has consisted of relatively small operations 
around machinery, etc. The auxiliar\ plant of two 2-cub. yard mixers, which 
li;id been ii^ service about 1 vventy-sexcn months east of the upper approach to 
(ialun locks, was closed on March iilli, i(ji2, :\n(\ on August ]6th, 1913, the 
dismantlement was begun of the l<'Ug<; installation on ihe west side of the locks 
known as plant \o. r, a description of which, with its electric services from 
the stock piles and to the ca))l(:\vays, appeared in CoNCRi-rPK and Constriic- 
TIONAT, Excij\EP:Ri\(; of May, rc)r(. This plaiil dniing its four years' service 

* " CoiicrcU; Constrnclioii m ilic )'aii;im;i (.;iii;il. ' ' ( ONCKKTI'; AND (^o.NSTlU'CTlo.VAL ICngINEERING, 

May, Juiu;, and August, I'^ll. 

I s2 



ry,cr;NMPiK-noNAil CONCRETE MASONRY IN THE PANAMA CANAL 

IkkI mi\i-(l ()\cT i,()00,ooo ful). y;ii(ls of roncrrtc. A tliir<l l;ii-c i)l;mt, r(iiii|)|)«(I 
with 1\V(» j-rul). vard niixiis, icniaiiu-d in use a lew months longer, Ijul lor the 
compUtioii of the liych-()-ck>rlri(^ power house two i-ciih. yard jiortahlc mixers 
have hiH-n used. llie two l)erni and four chamber eranes, of wliieh illustrated 
deseriplions were j^iven in this jouinal of June, 1912, employed at I'edro Miguel 
from April, ic)io, were transferred to and i)la(-ed in ser\ ice at Miraflores 
l)etw(>en Aj)rii, ii)ii, and Marc-h J()th, i()i2; and, with other herm eranes, used 
lirsl at Miiallores, wimc linallv disimmtled after July of last year. 

ATLANTIC TERMINAL DOCKS. 
Concrete will figure very j^ruminently in the construction ol the docks at 
the Atlantic entrance of the Canal and of the more extensive terminal facdities 



Panama PP. 




PANAMA CANAL 



Fig. 2. Dock Accommodation at Cristobal. 
CoNCRKTE Masonry in the Panama Canal. 



planned at the Pacific end. As will be seen from the accompanying- illustratiort 
{Fig. 2), the docks and anchorag-e basin provided and contemplated south of 
Colon will enable vessels to discharge and take on cargo without entering- the 
Canal itself. The preliminary borings at the site having indicated a good 
bottom, it w^as decided to adopt the method of concrete bulkhead construction. 
In the case of the works already completed or in hand, steel cylinders 10 ft. in- 
diameter and spaced 20 ft. from centre to centre, were sunk to bed rock, then 
filled with concrete and connected by a solid bulkhead of reinforced concrete 
sheet piles, 12 in, by 20 in., driven to a point 15 ft. below^ the lowest dredging 
of the channel. A steel girder encased in concrete, joining the tops of these 
cylinders, and a 24-in. I beam, similarly encased and placed 15 ft. below the 
water line, take the thrust of the piling. The cylinders are tied together in 
pairs directly across the width of each pier, and the area with bulkheads are 
filled to floor level, 10 ft. above mean tide, and co\ered with a floor of surface- 

153 



JOHN GEO. LEIGH. 



[CONCBETEJ 



hardened concrete havino- a total sustaining- capacity, including- live and dead 
loads, of I, GOG lb. to the sq. it. The project provides for two docks or quay 
walls on Cristobal Point and for a number of piers jutting- into the ship basin 
from a mole. For the present, however, only the two docks, a part of the mole 
and one pier have been constructed, the remainder of the work being- left 




COROZAL 



BAY OF PANAMA 



Fiti 3 Kerlaimed Land at tlie Pacific Entrance. The area bounded by the main line and the Balboa branch of 
the Panama Railroad has been reclaimed by hydraulic filling. See also Frontispiece. 

CoNCRKTK Masonry in thk Panama Canal. 

for execution as need for it may develop. The docks are 426 ft. and 
1,042 ft. long- and 209 ft. wide, while the pier has a length of 1,1 gg ft. and a 
width 01 75 ft. f) in. The dock superstructure is entirely fireproof, the walls 
being- oi reinforced concrete, 5 in. thick, and the roof of concrete slabs, 
reinforced with cxjjanded metal. In tlie su|)erst ructure there have also been used 
u\)()U\ 3S^j trms of slc'l. i'or other parts of the work there ha\e been, or will 
be, refjuired Oj^ steel cylinders, 152,565 cub. \ards of concrete, 402,000 lin, ft. 
of reinforced roncrctc sheet pihng-, 1,500,000 lb. of steel girder and ab(Hit 
800,000 II). of sled I l)eani. 

THE NEW PORT AND TOWN OF BALBOA. 

The frontispiece in th<- j)r(srnt issue of ( "()\cki:'|-Iv .wd Constructional 
I{\(;inf:f:rin(; is a view of the j'acilic entnince to the Canal and of the site of the 
P'fM't and tfjun of Ualboa now in (oiirsc of const rucl ion. As (;viden(XMl by this 

'S4 



J, Cr>N>TP«KTIONAL 



CONCRETE MASONRY IN THE PANAMA CANAL. 



I)lu)l()i4r:il)h aiul, in liilirr (lfl;iil, 1)\ I'i^. ;,, iiiiicli of llic land iiniiu diatcly 
i-asl of tlu' railwav \ai(l w liicli is to !)«■ l>iiill aloiijL; llu- iiiiuT ends ol Inc piers 
(It'sii^iu'd to hound oiu- side ol llu" future harl)()ur is reclaimed swainj), formerly 
rMiiidiuL; from tin- l>alhoa hiaiich of the Panama Raih'oad to the main hue. 
ll CON tied an ,uea of 400 acres, and ahout 5,000,000 cuh. yards ol material 
lia\c I)ccn used in raisini^ its surface' 15 ft. al)o\ c mean sea Icm'I. I'or exlendinj^ 
tin- inner haihoui to its uhimatc |)i()])osed dimensions other s\\am|) land will 
recjuiie to he dredged. 

Work on the reinforced concrete lumher wharf, or ])it'r No. 1 (see /m'/^.v. i 
and S), the first of the permanent improvements taken in hand in the harhour at 
the PatMlic end of the Canal, was commen(\'d in h\'l)ruary, 191 i. Kssential 
features of tliis erection, the superstructure of which was he^un on Dccem- 
iier 2nd, 1911, and completed in little more than two months, are (a) two rows, 
35 ft. apart, of solid concrete caissons, 50 in number, 8 ft. in outside diameter, 
and placed on 30 ft. centres; {b) main g-irders, resting on every set of caissons 
and extending- the width of the wliarf, 55 ft. ; (c) eight axial beams, bridging 
the spaces between the main g-irders and heavily reinforced at their junctures 
with the latter, and [d) on these supports a concrete floor, 6 in. thick. 

The tops of the caissons are 10 ft. above mean sea level, and the surface 
of the floor at elevation + 17. The concrete filling for the caissons, which was 
reinforced from ground rock to top with four double rows of old French rails 
connected by fishplates, is continued into the forms for the main girders, the 
latter and the caissons being thus set monolithically. The ends of each girder 
are embedded in a block of concrete 5 ft. wide at the bottom, where they join 
the caisson filling, the rectangular cross-section in the parts projecting beyond 
the caissons being 2 ft. 6 in. thick and 4 ft. 8 in. deep. This is reinforced with 
16 bars of i in. and ij in. twisted steel, enclosed in stirrups of twisted h in. 
bars. 




nr<> ^^ ^o i>' C:' I*'" -i' t 



a.S- 






JS.'O" 



ss.o 



r^7 




Fig. 4. Cross- ection between Piers. Ball^oa Lumber Wharf. 
Concrete M.\sonry in the P.\nama C.^nal. 

In the following sketch, Fig. 7, is shown the juncture of a girder with a 
caisson. On the water side of the wharf runs a railway, directly over the outer 
row of caissons. All beams, except the two at the wharf edges, are 15 in. thick 
and 3 ft. 9 in. deep, the edge beams being 14 in. thick and 3 ft. deep. 1 he 



:>:) 



JOHN GEO. LEIGH. 



ICGNCCETEJ 




Fig. 5. Gatun Upper Locks. Luukm^ North from tlie Lighthouse on Centre Wal 




Fif4. 6. Sinking Caissons for Foinidations, Mirafl(jres Upper Locks. Construction of North Approach Wall. 

C(JNCRI:TK MAStiNKV IN THK PANAMA CaNAI,. 



i;6 



d 



CON.STUUCTIONA 



^ 



CONCRETE MASONRY IN THE PANAMA CANAL 




Juncture of Girder with Caisson, 



main reinfonx'niciit in llu- middle of cacli beam 
consists of ci^lit i-in. twisted bars, willi stirrups 
of f in. twist placed about every j8 in., and the 
rail beams ba\e, as additional reinforcement at 
the junction with the main girder, two i|-in. 
twisted bars, extending- into the j^irdcM' from each 
side, or four at eacli caisson. 

Four feet below mean sea level, or 14 ft. 
below the loj)s of the caissons, the caissons c)f 
Balboa Lumber Wharf. the outcr row are joined together with tie g-irders, 

CoNCRKTE Masonry IN THE Panama CANA...3j^^j ^^ ^Y,^. same elevation a tie girder ex- 
tends from the caisson across to its mate of the 
inner row. These tie girders are 2 ft. deep and 22 in. thick, and are reinforced 
witli eight I in. twisted rods, with J in. stirrups. Each caisson of the inner 
row is anchored by means of a steel rod, 1;^ in. in diameter, extending- about 
10 ft. to a *' dead man " buried 7-2- ft. underg-round. This " dead m.an " is of 
concrete, ^^ ft. by 3 ft. by 3^ ft. in dimensions. 

The junctions of successive panels of the superstructure are made midway 
between main girders. The reinforcing- rods for the beams extend continuously 
from girder to girder, and, accordingly, for each panel the girder and the 
beams extending on either side were laid simultaneously as a solid mass of 
concrete. For each uniform panel 102*4 cu. yards of concrete — cement, sand 
and rock in the proportion of 1:2: 4 — were used. A panel was laid every 
fourth day, the interval being required for placing- the forms and the reinforcing- 
steel. In its complete form, the wharf, which is 656 ft. long, presents from 
below an imposing appearance of strength and durability, with a graceful Doric 
effect in the sweep of beams and g-irders. 

For commercial use there will be built a quay w'all, or wharf, in two 
sections, with a total length of 3,235 ft., in addition to 1,860 ft. in the neigh- 
bourhood Oi the dry docks, together with piers at right angles to the axis of 
the Canal, with their ends about 2,650 ft. from the centre line of the channel. 
These piers will be 1,000 ft. long and 200 ft. wide, with slips of 300 ft. between, 
and landings for small boats at the head of each slip for the full Avidth between 
piers. The main dry dock, designed to accommodate any vessel which can 
pass through the Canal locks, will have a usable lengfth of 1,000 ft., a depth 
over the keel blocks of 35 ft. at sea level and an entrance wddth of no ft., the 
entrance being- closed by mitreing gates similar to those used in the locks. The 
sides of this dry dock, as well as of one near by, having a usable length of 
350 ft. and a width at entrance of 71 ft., will be lined with concrete. At the 
outer end of south-east approach wall to the dry dock will be a coaling plant 
capable, in the first instance, of handling- and storing 100,000 tons. 

The large quantity of caisson shell required as supports for the piers and 
wharves has resulted in the evolution of a special plant for its manufacture. 
Of this the essential feature is a movable mixer, mounted on a flat car, which 
is shunted beside the platform on which the collapsible forms and the reinforce- 
ment for the sections are set up. Coupled to the " flat " is a box car con- 
taining- cement, and at the other end are alternate cars of sand and crushed 



:>/ 



JOHy; GEO. LEIGH. 



fCDNCBETEJ 




158 



y^coNMpncTioNAi.) CONCRETH MASONRY IN THE PANAMA CANAL. 



rot-k, ;ill coniUHli'd in lr:iiji and moxcd as a iinil. Wlicn llu- train is brought 
()ni)()sitf to a form which is ready the concrclc is poured into the latter tliroug-h 
a cluile, tlu' sjK)ut l)eini^ al)ou! i^ It. ahoxe the platform. 'llu- concrete is 
allowed to set for twent\-four houis, after w liich the foiins are remoxcd lo a 
spiH-ial |)lalfoi-m to be cleaned and then relnrncd to the ()])eratin^- ])latlorm; but 
the c-aisson shells remain foi" three days to hai'den befoic removal to a storage 

\ard 

At one v\m\ of the platform on which tlu' forms are set up and iilled is in 
extension on which the reinforcing- steel is assembled. As the bars are unloaded 
fron-. the cars thev are l.iid in a stock pile at the v\u\ of the platform and close 
to a set of steel rolls. The rods are fed directly into the rolls, which are set 
to l)end them into hoops of a diameter 4 in. kss than the outside diameter of 
the finished shell. The bars are set up around a wooden cage and tied tog-ether, 
after which the reinforcement is handled as one piece. A iig:ht derrick mounted 
on a truck picks up a set of reinforcement, carries it to one of the erected inner 
forms for the shells, and drops the reinforcement around it. Then six pipes 
are placed vertically around the reinforcement at equal distances to make cores 
for connecting- rods; the outer form is erected; the space between iorms is 
adjusted with wooden blocks, and the completed form is then ready for the 
concrete. Each section of shell is i ft. thick and 6 ft. high, has an inside 
diameter of 5 ft. 6 in., and contains 45 cu. yd. of concrete. In all, about 
28,000 linear ft. of concrete caisson have been used in pier No. i and the 
adjoining- qua\- wall ; and both concrete and steel shells — the latter being- used 
in deep water because of their greater length — are filled with concrete containing* 
a well-protected reinforcement of steel rails. 

Extensive, indeed, almost exclusive, use is being made in the construction of 
the permanent buildings in the new town of Balboa of reinforced concrete and 
hollow concrete blocks. The latter have been produced on the Isthmus by what 
is known as the Pauley steam jacket process. During the early part of last year 
Mr. Albert A. Pauley, the patentee, was appointed by the Canal Commission 
to superintend the erection of the necessary manufacturing plant, and he 
remained on the spot until the work of making the blocks was well under weigh 
and others had been thoroughly instructed in the operation of the machines. Of 
these fourteen were obtained from the United States — two for making- founda- 
tion blocks, 12 by 12 by 24 in. ; six for main wall blocks, 8 by 8 by 16 in. ; two 
for corner blocks, 8 by 8 by 16 In. ; one for partition blocks, 4 by 12 by 12 in. ; 
one for interior columns, 3 by 12 by 12 in. ; and two agitators for stirring the 
concrete before its passage into the block machines. It is stated that each 
machine is capable of turning out a block every five minutes. The blocks are 
kept under a constant spray for twenty-four hours, and are then allowed to set 
for about a week, when, normally, they are ready for use. 

{To be continued). 



159 



H. KE UPTON DYSON. 



ICONCBETE! 







TT^rw.-^^<t; 



SLENDER STRUTS^ 



By H. KEMPTON DYSON. 

The foUoiving article has been ivrHten by the Author to further explain the question 
of loads on pillars, •which ivas touched upon by him in his articles Tohich appeared in our 
journal last year on the London County Council Regulations on Reinforced Concrete, — ED. 



A GREAT deal has been written about the strength of slender pillars and struts, and 
many formulae have been proposed for calculating the resistance of such members. 
The majority of these formulae are in the nature of practical rules of a roughly 
approximate character. A few have been developed upon what may be termed rational 
lines, although it is always ambiguous to speak of one formula as being rational and 
of another as being empirical, because the fact that the latter word signifies something 
resting upon trial or experiment, or known only by experience, makes it apply in a 
way to that which is rational or reasoned, for the rule derived by reasoning from 
observed facts is thus itself the outcome of experience, and can only be employed in 
connection with factors the values of which are derived from experiment. The common 
meaning, however, is that an empirical formula rests upon the records of tests on 
model or full-sized members and/or upon the results of experience in the practical use of 
full-sized members, while rational formulae are derived by the application of mathematics 
to the properties of materials as determined by laboratory experiments. Perhaps a 
better word than " rational " would be " absolute." The kind of formulae generally 
known as Rankine's and Gordon's formulae for struts are of the empirical character, 
while Euler's formula is of the absolute or rational type. Of course, Rankine's and 
Ciordon's formulae have been drawn up upon some sort of reasoning, but they contain 
constants which are ultimately derived from experiments on model or full-sized struts. 
Neither absolute nor empirical formulae can, of course, be asserted as exact, because 
they ultimately depend upon properties of materials about which the very nature of 
physical science precludes us from surely dogmatising. 

This article is the outcome of the consideration of the extremely onerous 
rules for determining the loads permitted to be put on pillars by the pro- 
jjos(-d Regulations for Reinforced Concrete made by the London C^ounty Council 
after preliminary revision by the Local Government Board. It is not the 
purpose of this article to deal in detail with the mechanics of struts, that subject 
having been so often threshed out, but rather to aj)ply to reinforced concrete 
what the writer consid(;rs to be the most scientifi(\'ill}' practical reasoning in respect 
to the determination of the resistance of struts which has been put forward. In the 
writer's opinion the most scientific analysis of the theory of the resistance and the prac- 
ticnl dfsign of sU-nder columns is th.-it given by Mr. William Alexander, M.Inst.C.E., 
in his book entitled " ("olunins and Struts." Seeing that the subject is there discussed 
in considerable detail, it will be unnecessary here to go into the matter so fully as he 
does in that book. 'Jhe unsatisfactory n.'iture of the older type of rule, derived from 
an inadequate analysis of the problem, lias made engineers nervous in the use of such 
formuLx', especially in view of the failur(; of Ouebec Bridge in t()07, which, it has been 
asserted, showed that we [)Ossessed inadec|iiate knowledge as to the behaviour of struts 
that were considerably larger tli.-ui those upon w lii( li experimenis had so far been made, 
thereby confessing that the customary formula' could only be applied with a feeling 
of security so far as tested by exjx'riments on full-size members. That, of course, is 



l6o 



^1*, ClON.VIUlKTICMAi: 
A KNGINKKRINCi — 



SLENDER STRUTS. 



;in iiin.ilc faull in llic ( iii|)iriiMl lormul.'i-, .ind, .illliou^h we should Icsl formula- of \he 
absoluU' t\[)c l)\ cxpcriinciil in order to sec lh.it (hero is no fundanicnlal ciror in tlicir 
dt'i'ivation, we ft'<l much moic c-onlldcnl in their use because they are certain to apply 
to cases outsidt liu limits of known experiments, excn if they have to be modified 
slii^hth. The absolute formula' have been xcrilied by such exf)erimental work, and 
Mr. William Alexander, by making several sim|)lifyinj^ approximations which make no 
appri'ciable difference to the values obtained, has succeeded in arrivinjf at a very 
piactical tvpe of formula of i^'eneral ap|)Iication. 

The [vuc curv(> into which a strut is bent by the application of a load apj)lie(l directly 
at its ends is called the elastica or lintearia. A strut will not start to bend until a load 
of a certain amount is applied. The absolute formula which j^ives the limits of loads 
that will start bending' may be derived in various ways, but it was derived in one way 
bv Euler and is known as Euler's formula. As a strut bends more and more its 
resistance to bendini^ increases, and the load that will start bendin^j is therefore not 
so great as the crij)plin£^ loads. Euler's formula makes it appear that the strenj^th of 
a strut varies inversely as the square of the len<;th, but this is not absolutelv true, 
thoui;h, within certain limits, is nearly so. Tredi^old ori<4inally developed the type of 
formula known in two forms as Gordon's and Rankine's. He assumed a length of 
rectangular strut of uniform cross section long enough for bending to be likely 
to occur. 

Referring to Fig. 1, let 

P = the total pressure or load on the strut. 
/ = the length. 

■■i =the cross-sectional area. 
^ =the deflection at the centre produced by the load. 

P 
pd = the intensity of direct pressure = . • 

pb = the intensity of pressure due to bending. 
^ = the least diameter of the strut. 
b = the breadth of the strut at right ang es to d. 
w = intensity of ultimate fibre stress. 
C = a constant. 

If we regard the cross section at the middle due to the bending 
moment caused by the eccentricity of the line of application of the load, we have : — 

pb vanes as -— :;> 
ba- 

it being assumed that the bending will take place in the direction of d. 

Then assuming that the deflection varies directly as the square of the length and 
inversely as the diameter, we have — 

I' 




Fig. 1. 



while 
Therefore 



^ varies as ^> 
a 

bd' varies as Ad. 
P I 



pb varies as 



A 



I' 
, or as pd-.^' 
a' a 



But // =pd-\-pb. Therefore u 



-li^-O 



(1) 



A strut with pin-connected ends being twice as flexible as one having its ends fixed 
in direction, the constant for pin-ends needs to be four times as great as for fixed ends. 
Therefore, as the fixed-end type is the stiffest possible, its constant will be the least, 
and if we call this C,, the corresponding value for the pin-ended type is 4C,. 

Transposing the foregoing equation, and including the constant for pin-ends, we 
have — 



iiA 



d 



^2» 



161 



H. KEMPTON DYSON. 



[CDNCKETFJ 



Hodf^kinson carried out numerous experiments on cast-iron and wrought-iron 
pillars, from which Gordon suggested value> of the constant C ., and the formula 




is generally known as Gordon's formula. The value of the constant as given by Gordon 
varies ver}- much with the form of the j)illar, namely, as to whether it is rectangular 
or circular, hollow or solid. Rankine therefore substituted for the factor d- the value 
i2g'- (in which ^'^the radius of gyration of the section in the direction of bending) 
because, the sections on which expi-riments were made being rectangular, (/-=i2o-. 
Rankine 's formula is therefore — 

P= ''^. (4) 

'g' 

and is often called the Rankine-Gordon formula. 

The assumptions in it of the strength varying inversely as the square of the 
length, II varying directly as P, and that bending will take place in the direction in which 
g is least, are all untrue. The one constant employed in the foregoing formula has to 
provide for all possible causes of departure from ideal conditions that are met with in 
practice and for all the effects of variation in the form of cross-sections, while as 
employed it is distinctly empirical in that the constant is chosen so as to make it agree 
with the average results of as large a number of experiments as possible, without 
discrimination. 

\'arious modifications have been pro]3osed in this formula to cover observed deviations 
from the predicted results, but fundamentally they are all inexact, being based on 
assumptions which are not absolutely true. 

Absolute formulae for bent struts entail the use of elliptic integrals and are not 
very convenient of application. There is no need to give the formulas here — thev are 
set out in detail by Mr. Alexander, who shows that Euler's formula is only a singular 
value obtainable from the general equations by setting the limit that the deflection 
shall be nil. 

Euler's formula is 

the meaning of the symbols being given later. 

Mr. Alexander goes on to show how if values are assigned to the intensity of 
ultimate fibre stress (such as limiting it to the value of the elastic limit or yield point) 
and to the direct compressive stress the absolute equations become determinant as to 
the ratio l^/^, giving results which show in an ( xtrcnic case '23 per cent, increase on the 
value of Ic ^ obtained from Killer's formula a c|uile negligible amount as regards the 
calculaticjn of the saf(; resistance, though making all the difference as regards the 
determinatir)n f)f the deflection and curvatur(.'. For ideal conditions of loading, therefore, 
we may substitute luiler's formula for all practical j)Ui[)oses, but we must remember 
that if we set a limit trj the value of p,j \\c iinill llie value of ^j//c, which shows that 
below the value thus obtained no bendini; will resull and we could load the section to the 
full limiting dir(!Ct stress, in practice, howe\cr, we ne\'er obtain ideal conditions, the 
departure therefrom being in respect to in<t|iialities in llic manufacture causing a want 
of homogeneity in the material resulting in a \aiialion in llie value of the modulus of 
elasticit\- from p(jint to [joitit of ;i section, ;ni(l the w.nil ol alignment in the longitudinal 
axis resulting in th(* load at ihc end of the slrul being applied out of its longitudinal 
axis. These main causes rmd some mitior ones rcNuIi in a sliut deforming more on one 
side th;in on another, and m;i\ all be I.Mken togelher as accideiil.il ( ccentricilx' in the 
application c>f the hjad. 

Mr. Alexander shows how by an .-ipproxiniat ion lliat invokes a |)racticall\' negligible 

163 



' <V EN(.lNKKWlN(i ^. 



SLENDER STRUTS. 



error wf can (•\|)r('ss the cUccIs oI .suth tccciUric- applicalioii of ihc load by the loIlo\vinj4 
moiiiru-ation of I"!iilcr"s fonmila : — 



(7) 



/' '2 ^ A' />J 
whon^ .1 - rc.i of strut. 

I'l inoclultis ol elasiicity. 
£' = eccentricity of line of thrust (see 7-'/^'. 2). 
^ = gyration radius. 
/ = moment of inertia = ^^'. 
/f = l(Mi,<;th from cen re point of a curve to a point of contrary 

ti ex tire (sec F/^'.v. 2 and 3). 
»= distance of extreme fibre of cross-section from the neutral axis. 
P = total load. 

P 

/></ = direct pressure intensity = 

^6 = pressure intensitv due to bending. 
;/ = permissible ultimate strength of short concrete specimen =pd-\-pb. 
= qualifier of reduction on direct compressive stress. Therefore (JuA — 
maximum load sustainable. 
Both this and Euler's formula will now be put in a form specially suitable for 
plottinj^ on a diagram. 

Thus, substituting Pb = i( —pd, pd = Qu and I = Ag', in (7) we have 

]]. = \/EAg'^ "^ _e .n . pd ,\ 
"P '2 g g u -pd ^ 

pdi2 g g u-pd^ 




h'g = 



-\/ E\ 



e n 



Qu 



^ Qit\2 g'g'u-Qu^ 



= V 



E 



e n 



V O 



'' <2a'0 ^ ^ (1-Q) 



Also substituting in (6) 



2 Pd Oil 2 u 2s O 



(8) 



(9) 



A formula of the Rankine-Gordon type may also be derived in another way, which 
gives a form more suitable for plotting in conjunction with the foregoing. Thus : — 
If a column is very stiff, then it is true that 

Ps = uA (10) 

while, if it be very slender, Euler's formula will be true, and 

Then the equation 



11 



P Ps Pe 



(12) 



fits the condition that when the strut is very short strut P = Ps nearly (for in this case 



1 



1 



——becomes negligible), and for a long strut P = Pe nearly (for in this case — becomes 
negligible). Therefore, by substituting (lo) and (ii) in (12) we can write — 

1 1 //.4 



Ps'P, nA^-n-'EI 



4ulc'A 



[u: 



C 2 



163 



H. KEMPTON DYSON. ICQNCBETE] 



and P= 4,,^^.4 (14) 

From (13) we obtain Ranking 's formula — 

nA 4n 

P= ',■> where C, = -^^ (15) 

1+cA ■ ^^ 

■g 

and also (iordon's formula — 

P= pr where ^]^ ^p^j ' ^ being the numerical 

i + Cf,, 

coefficient in the equation I = XAd'. 

From (14) we see that the value of O by Rankine's formula is — 

1 _ 1 

Calculations of the resistance of struts by the foregoing formulae are most easily 
performed by the aid of diagrams and Ruler's, Rankine's and the modified Alexander's 
formulse have been plottc^d by the writer on Fig. 3 

In using this diagram, except for the Euler and Rankine lines, we need to determine 

11" ^ 
the value 01 a constant marked ~ • — 

g g 
The determination of this constant depends upon our choice of c because the value 
of H and the value of g are strictly determinate, depending only upon the form of the 
section. In giving values for e (which is the eccentricity of the line of thrust in the 
strut) we have to bear in mind the practical conditions under which struts are employed 
in practice. The causes of departure from ideal conditions of true axial thrust have 
already been referred to. Of course an eccentricity obtained by design is known, but 
we require to gain some idea of the accidental eccentricity. F'irstly, we may consider 
the eccentricity that may be due to want of homogeneity in the material, which results 
in a variation in the value of the modulus of elasticity from point to point of the 
section, and causes a want of coincidence between the geometric axis and the neutral 
axis. This is very clearly shown in the case of the ordinary theory of the position of 
the neutral axis in a reinforced concrete beam where two materials of very different 
moduli of elasticity are being used. In a steel strut we know that the material will 
show a very appreciable difference in the modulus of specimens cut from different parts, 
which means that if the section be loaded it will give way more in one direction than 
in another, and the neutral axis will therefore be disjjlaced from the geometric position. 
In a reinforced concrete pillar, as a rule, the steel sections are symmetrically placed, 
but whfthcr due to incorrect placing, or whether from the somewhat greater risk of 
want of homogencits' in the concrete, the neutral axis of the combined section, in which 
the steel has a different elastic modulus to the concrete, will surely not coincide with 
the geometric iixis. Internal stresses are, of course, another minor cause of irregularity. 
.Such intf-rnal stresses may result b\' contraction of the concrete or b\- the rolling of 
the steel and even by changes of teiiipeialure. The \ariation in the modulus of elas- 
ticity will in all probability take place o\er a smaller range as the sectional area 
increases, br•(au•^e witji the larger section the average value would he more uniform. 
Then again, the longer the (olunin the grealei- |)i()hal)ilily of uniformit\', because as 
the length increases the lunnber of ( ross-scclions increases, and with it the |)robability 
that variations in the modulus will not lake place in the same direction in all of the 
sections, so that one will iieutt;ilise the other and the resulting effect on the wdiole 
will decre<ase. Therefore wc may say that any ( c( ( iitii(il\- in the load due to \'ariation 
in the modulus of elasticity will show a decrease with an increase of the lateral dimen- 
sions (which is the samr- thing as saying the radius of gyration) and with increase in 
the length of the strut. The net residt is therefore j)robal)ly that variation in the ratio 

164 



y, C^UN.vrUMK-nONAL 
»^ L.N(ilNhl.klNti — ; 



SLENDER STRUTS. 




Values of Q (Redact/ on c^ua//f/er for O/recf Stress) 



Fig. 3. 



[Copyriglit reserved by author.] 



of Ic g ^"^'ill not appreciably effect any variation in the accidental eccentricity. The 
second and most fruitful cause of eccentricity is inaccuracy in workmanship, whereby 
the strut is not properly centred or put in true alif^nment. We should expect that any 
difficulty in manufacturini^- the strut and putting it -nlo place so as to secure axial 
loadin<:^ will certainly not be decreased with an increase of its length. Therefore it 
should be assumed that the longer the strut the greater the accidental eccentricity due 
to inequality of workmanship. Finally, we have eccentricity due to the application 
by design of a load out of the centre. This, however, is of known value, and may be 
ignored when we are endeavouring, as at present, to arrive at some reasonable values 
for the two causes of accidental eccentricity before referred to. 

In building work it is seldom that columns are fixed at one end and are free, or 
merely hinged at the other, although, perhaps, in the majority of cases the colurnns are 
not properly fixed at the ends. As to what value should be given to the accidental 
eccentricity due to variation in the modulus and internal stresses, we can only go by 
experimental data, from an inspection of which it would appear that we should set 

i6; 



H. KEMPTON DYSON. ItQNCKETE 



the limit undtr the vei v best conditions — i.e., in the case of struts which are adequately 

fixed at the ends — that the value— should never be less than o'l. 

We now have to derive a reasonable value to take for the eccentricity that may be 
due to a strut not beinif set in its true alignment. The mere placing of a strut out 
of centre, apart from the question of it being inclined to the line of thrust, is not likely 
to vary much in amount with variation in size, and consequently becomes less serious 
as the lateral dimensions increase. Such variation is already sufficiently provided for 
bv the foregoing allowances. The difficulty of setting a pillar upright is, however, an 
important matter. If we assume that in practice a short pillar 5 ft. long may be put 
h in. out of the upright, and that this might be increased to i in, in the case of a strut 
10 ft. long, we couki express this as a rule by taking the eccentricity in inches as o'oi/. 
The possible eccentricity due to variation in the modulus becomes negligible in such 
cases compared with this eccentricity due to imperfect workmanship, and may be 

ignored, so that the writer arrives at the conclusion that the accidental value of - 

should in no case be taken as less than o'l, and otherwise that the value should be 
derived by assuming e to be either o'oi/ or one half-inch, whichever is the greater. The 
accidental eccentricitv due to inclined setting of the pillar derived in this way will be 
fully effective in the case of a pilar fixed only at one end and perfectly free at the other, 
as shown in Fig. 2, but will be reduced in the same proportion as the total length I is 
reduced to J^. bv being forced to bend in various ways for various manners of end 
holding. 

In order to apply Alexander's formula we need to ascribe values to the other con- 
stants, namely, Z^., E and u. As regards the latter, namely E and u, it must be recollected 
that the formula applies solely to the limiting condition of the practical ultimate strength. 
Indeed that also is the case with both Rankine's and Euler's formulae. In the case of 
steel the modulus is only fairly constant up to the yield point of the steel, but as the 
values we have taken above for determining the accidental eccentricity provide for 
variations in the modulus, the limiting values become^ =30,000,000 lbs, per sq, in,, 
and M = 50,000 to 55,000 lbs. per sq. in. in the case of steel, the latter being the yield 
point, and the ultimate compressive resistance for ordinary mild steel. In the case 
of cast-iron, timber, stone, and plain concrete there is no uniform value of the modulus, 
this becoming less as the stress increases. We may, however, tak(^ the average modulus 
over the whole period of loading; thus we derive the value of E by taking the ultimate 
stress and dividing it by the ultimate strain. In the case of a compound section of two 
materials like reinforced concrete, we are faced with the difficulty that the concrete has a 
variable modulus while the steel has a comparatively imiform one, and therefore the rela- 
tion of the one modulus to the other is constantly changing, which means that the equiva- 
lent section, namely, that in which the ai ea of the steel is nuilli|)lied /u-fold, in being the 
ratio of the moduli of elasticity, EslEc, '^^ likewise continuously changing. The diffi- 
culty is, however, solved for us by the simple consideration of what happens to a 
reinforced concrete pillar when it is loaded to destruction. We find that as the stress 
increases the concrete is strained faster than the steel, and consequently the stress on 
the steel is continually increasing at a faster rate than the stress on the concrete until 
at the ultimate load the concrete is carrying all that it is al)le to sustain and the steel 
is forced in turn to carry the remainder of the load up to its maximum resistance. The 
two materials therefor(,' break down together. Assuming, therefore, that the steel has 
a uniform mfjdulus, up to that j)oinl, of 30,000,000 lbs. per sq. in,, and that 
stress-^strain ^modulus, as the strain is the same for both materials we have the 
relation : — 

Strain lu ! u c — Eslu $ 

tic 
frfjHi which Ei E<,. 

lis 

Supposing, therefore, we li;i\c ,1 (OIK I etc wjiosc uliiinale compressive resistance is 
2,400 lbs. per sq. in., win 11 iIh ujiinialc coiiiijressivc! strength of the steel is 50,000 lbs. 
per sq. in., we find from the above thai the nuxluhis of the concrete 



Ec = 30,000,000/ ^'^°^- - 1,440,000 Ihs./in," 



166 



fj, CrJN.vrkMKTIONAI 
L*^v t-NC.lNt-I RINC, — . 



SLENDER STRUTS. 



30.000.000 
or He- 3^^^^^,^ .,/,-600.. 

Tlie niodiilnr ratio will, of course, be m 



Rs Its 50,000 



Hi u uc 

'i"o juslify ilif ;uI()|)lion ol 5(),()()() ll)s./in- as the ultimate stress in the steel, the 
spaeiiii^; of the links should he close tiioui^h to enahle this stress to he developeci in the 
rods ici^ai'dcd as slender sliuls in themselves, i.e., the pitih of ihe laterals shoidd not 
be i^ri'ater than \{) times the diameter of the least vertical bar. 

In choosinj^ aN'eraj^e values for the idtimate (H)mpressive resistance of concret<', it 
should be remembered thai the limits customarily set to the minimum strength required 
by specifR'alions, re])orls and regulations to be shown 1)\ tests on moulded cubes do not 
represent axcrage \alues nor the actual strength of concrete as put into the work in 
practice. The author has already dealt with this in an article on pp. 604 and 605 of 
the issue of C^oxcRiiiE and Constructional I^\(.infkking, Vol. N'lll., Xo. 9, Sep- 
tember, 11)13. The average strength in practice \\ ill i)ossibly be 20 ])er cent, higher than 
the values obtained from test cubes, while in the event of the maximum stress being 
realised only on the extreme libre the ajjproximately parabolic stress distribution due 
to variation in the modulus of elasticity of concrete as the stress increases will serve as 
an additional reason for trd^ing a higher value than the limit set for test cubes. 

It onlv remains to find the value of /, • This, of course, will vary for different 
conditions of ends and for different values of the eccentricity and different ways in 
which it is applied. An exact solution is difl'icult to derive, and the usual conditions are 
generallv not de])arted from sufficient ]\- to make it worth while determining its exact 
value. Indeed, to do so would mean emj:)lo\ing the long, unmodified absolute formulae, 
and considering the other factors are not known with any great degree of accuracy it 
would be in great part a waste of time. The value of I^ is therefore best derived for a few- 
standard cases and under ideal conditions, namely, by Euler's method. 

In the case of a strut fixed at one end and free to move at the top (as in Fig. 2) the 
value of I ^ is obviously equal to /. 

In the case of a strut hinged at bcnh ends and maintained in the same lateral 
position, the value of /^ is I/2, the form of flexure being shown on Fig. 3. 

If both ends of a strut are rigidlv fixed and held against turning, the elastic curve will 
have two points of inflexion, and from symmetry the tangent to the elastic curve at the 
centre must be parallel to the original position of the axis of the strut. Therefore the 
portions of the curve must all be sxmmetrical, and consequently the points of inflexion 
occur at one-fourth the length of the strut from either end, and we get h =?/4. 

This may. however, be derived mathematically as follows (see Fig. 4) : Let both 
ends be fixed against turning by a moment M at each support. Then the moment at a 
point distant x from O is Mx = M — Py, and the equation of the elastic curve is 

EI. '-j^l = M-Py. 
ax' 

Integrating w^e have 

J ==^ sin ( ^ V£j^ + B cos ( X V£) + 1 

in which .4 and B are constants, which can be determined by the conditions that y = 

when A- = 0. We find thereby .4 =0 and B=—^—' Also i; = when x = L There- 

P -^ 

fore we have B cos I /V — W— =0. Likewise — = when a = / : therefore 

El P dx 



From these conditions, 



cos 



V EU 



167 



H. KEMPTON DYSON. 



lOONCKETEi 



and 

whence 

from which 
Also 

and 






M ( a/1^\ , M 



r/-T 



Equating "t^ to zero, we have 



cos 



xVl=0 



P 
EI 



and 



X 



\ — =: - or — 
El 2 2 



But as /V" = 27r, then V — = - 
EI EI I 

whence x= ~ or -/. 
4 4 



.^^ 



mO 



\p 



Fig. 4. 



Therefore the points of inflexion are situated / 4 away from the ends. 

In the case of a strut fixed at one end and hinged at the other, but not maintained 
bv the hinge in its original lateral position, being guided instead into a position where 
the lateral movement of the free end is half the total deflection, the elastic curve has 
ix>ints of inflexion at one-third and two-thirds of the length, as shown in Fig. 3, and 



(To be continued.) 



168 



J, coN.vrymTioNAi 



REINFORCED CONCRETE GRAND STAND- 






,i$|,U /« GRAND STAND. 4 

i. Vlit s-rT^-- HURST PARK 



I 



RACECOURSE. 






^ 



^•---^ 






Reinforced concrete is f^st replacing timber for structures such as ttie one described in the 
present article, and ive ha've already gi'ven -various examples of grand stands erected not 
only in this country but in the United States. As indicated in the article, reinforced concrete 
is particularlv suitable for buildings of this description, as there are practically no main- 
tenance charges. Our article has been prevared by Mr. Albert Lakeman, Hon. Medallist 
Construction.— ED. 

Owixd to tlic limber stand liaxiiii^ hci-n destroyed by lire, it l)ecanic necessary 
to reconstruct the t^rand stand <it Hurst Park Racecourse, and advantage was 
taken of this necessity to increase the accommodation, and at the same time to 
employ reinforced concrete as the material for the constructional m-embers, to 
pre\'ent a recurrence of a disaster of this kind. 

The new stand, as now completed, is one of the most up-todate and com- 
modious in the country, and it requires no maintenance, which is a very im- 
portant consideration. The total len^-th of the stand is 164 ft., and the width 
52 ft., while ir has a heig-ht of 36 ft. from the ground-floor level to the eaves. 
There are practically three floors, apart from the ordinary accommodation, which 
is capable of taking 7,500 spectators, and these floors are utilised for luncheon- 
and drawing-rooms and cloak-rooms. The luncheon-room on the ground floor 
for members is 62 ft. 6 in. by 39 ft., and in addition to this there are two grill- 
rooms, each 37 ft. 6 in. by 39 ft., one of which is for the use of members and 
the other for reserved enclosure ticket holders. The kitchens are provided on 
the first floor, and these are extensive and fitted up in an approved modern 
style, with every facility for efficient and quick service and cooking. The 
remainder of this floor is devoted to cloak-rooms for ladies and gentlemen. 
The second floor is designed to provide a suite of drawing-rooms, which are 
tastefull}- furnished and enclosed on both sides with glazed framing, which 
enables the users to watch the races in complete comfort, even in the most 
inclement weather. A splendid view of the entire course can be obtained from 
these rooms through the front windows, and at the back a view is obtained of 
the paddock, the casements being arranged to slide, thus enabling the rooms to 
be opened up during fine weather. Every effort has been made throughout to 
provide the maximum amount of comfort for members and others using the 
stand, and a central heating- apparatus is installed for heating the building 
throughout. 

The general heights and arrangement of the different floors can be seen 
in Fig. I, which is a cross-section of the stand. It will be noticed that the 
existing retaining wall at the front is utilised, and that the kitchens conie behind 
the tiers for the spectators, and thus no space is wasted. The whole of the 

I 69 



REINFORCED CONCRETE GRAND STAND. 



ICQNCBETFJ 



reinforced concrete work was desig-ncd and executed on the Mouchel-Henne- 
bique system, from details and drawings prepared by Messrs. L. G. Mouchel 
and Partners, Ltd., of Westminster. 

The genera! effect of the back of the stand, whicli is shown in the photo- 
grapli in Fig. 4, is interesting, as it will be noticed that the horizontal and 
vertical lines are obtained hv the reinforced beams and columns, while the 
panels are filled in with Mouchel patent monolithic hollow-block walling, rein- 
forced throug;hout and finished on the exterior with rough cast. A cross- 
section showing; the constructional members is g"iven in Fig. 3, and it will be 




■STEEL STANCHION 



EjriSTiNG 
«?ETA'.NINQ WAuT 



S - .';«i\ 






DRAWING ROOM 



LUNCHEON ROOM 



.j.^'^'-^'-*- 



KITCHENS -^ 



''JFt-J.-'-^.'-'.^^Tr^ 



li^!. ] Cross Section of Stand. 

RKINIORfEO CONCKEIK GkANI) StAND, HlKSl FAKK RaCKCOURSK 

seen ili.il ihcre are three longitudinal rows of columns S])a(^e(l at 12 ft. 6 in. 
centres. 'i"hc s];;icing was .dso (•(|iial to this amount in the longitudinal direc- 
tion, thus di\i(iing the l);i\ s n|) into jxTlcct s(|uar('S. 

These columns are all 1 ) in. sfpiarc, and they are reinforced with four 
lines of x'ertlral rrinfort ( incnl , with links at 4 in. centres, and they have a 
reinfijreed cont rele hjnnd.iiion ^l.il) .| ft. s(|nare and 5 in. lhi(-k at the extreme 
out<;r i-(\^c, inrreased lo 1 ll. ] in. al iIk jyoint of inlerseelion with the column 
shaft. TIh; slal.s aic reinlorccd wilh a lallice, consisting of rods in both direc- 
tions in the undeisifle, with comieciing stirrn|)s lanniing up to a similar lattice 

170 



d 



OON.STUIKTICMAL 



REINFORCED CONCRETE GRAND STAND. 




^Tlg 1)4 i^/^* 



Se.c:T»or-* P' ' V^ 



Fif,'. 2. View Showing Section of Stand. 




Fig. 3. Cross Section. 
Reinforced Concrete Grand Stand, Hurst Park Racecourse. 



171 



REINFORCED CONCRETE GRAND STAND. 



(CQNCBETFJ 



at the le\'el of about the centre of the deptli. The ir.ain column rods are turned 
out at right ang'les at the bottom to assist in tlie distribution of the weig^ht. 
The slabs forming' the lloors are designed on tlic continuous principle, and these 
are 4^ in. thick, with small bars in both directions and surfaces, and the main 
beams, as shown in Fii:;. 5, arc ih in. or 14 in. deep and 7 in. or 8 in. wide, 
and reinforced with cither lour !)r ciglil rods, according' to the load, half of the 
number being- placed in ihc upper and half in the lower surface. The two sets 
of reinforcement are connected by links, and where no rods are required in the 
compression area some of the bars are cranked up at the ends, and stirrups 
are provided at variable distances. 

The stepped portion which slopes back at the angle shown in the section 




V'\fi. 4. \'iew Shovvinf4 liack of Stand. 
KEiNroRCEi) Concrete Grand Stand, 1 1 lust Park Racecourse. 



is lorn"iC(i wilh treads 2 It. <> in. wide, and risers 1 It. 3 in. high. A detail of this 
W(jrk is shown in I'l^. -', and il will be seen that two longitudinal rods are 
placed ill llic sollii (lose to the intersection ol tread and riser, with stirrups 
carried well ujj into the mass ol the concrete. in addition to this, transverse 
bars are prtAided in the sollil which are cranked to pass o\er the longitudinal 
r(jds in each case. 

The raking" bf;ams supporling the slo|)ing |)orlion lake a b( :iring on the 
retaining wall al the loot oi the slope, the old concrete at the top of the wall 
being broken oil and rebuill wilh ihe beams to lorm a monolithic c-onsl ruction. 
The whole ol tlw slniciiirc,- is coxcred by a tool ( omposed oj steel trusses and 

I 7?. 



J , CONyrUUCTlCMAU 



RIiINFORCHI) CONCRETE GRAND STAND. 



42 



■ ~ H 






























^ 




'— r 

, U 


11 






-«::: 












^ 








^ 


^ 








H, 








1.? 


- 








- 


IL 


EVA 


1^ 


Or 




" 


. e . 


. /,<«, 


*** - 


:>, 


*• 
1 




• 



l<o 



._L4 ._ 



I m il 




IP 



n 



111 



12 <«=> — 



TT=? 



J>L 



Fif4. 5. Reinforced Concrete Main Beams. 





i7crA.L Or <^-.iovi>i-i A.13^«cl<.. 









4 


■ o 








» 








^ 


r 1 


T 


■ 


■y 






■] 


A 







\ 












/ 








\ 








/ 












^ 






/ 
























































/" 






"s- 






/ 








s 






, 


/ 








^ 




\ 




/ 










L 1 




\ 

























Fig. 6. Detail of Column. Detail of Slab. 

Reinforced Concrete Grand Stand, Hurst Park Racecourse. 



173 



REINFORCED C0NCRETE2GRAND STAND. 



[CQNCBETEJ 




174 



(K, OCffMM UUCriON A UI 



RHINFORCHD CONCRETE GRAND STAND. 



purlins, coNi'icd with wiouLjlil hoai'dini; , upon w liicli is l;ii(l ;i non-tl.inini.ihlc, 
(lur;ii)lc' loolui*; in;iU'ri;il. 

'llir whole schriiU' is well |)l;iMnc(l ;in(l consl rucl cd in such a niainifr that it 
is hri'-rc'sistinj^ and durahlr, and will rcijuirc j)i'a('t icalK' no n^.ainlcnancf, while 




Fii^. 8. A Corner of the Grill Room. 
Reinforced Concrete Grand Stand, Hurst Park Racecourse 



its appearance is simple and pleasing. The contractors for the general con- 
struction and reinforced concrete work were Messrs. Stephen Kaxanagh and 
Co. , of Surbiton. 



»7S 



STANDARD METHOD OF MEASUREMENT. 



ICQNCKETEJ 




"standard method 

of measurement 

for reinforced 

concrete, 



The following is the Draff ReportZof the'' Joint -Committee 
of Representatives from the Quantity Surzieyors' Association, 
the Quantity Surveyor Members of the Concrete Institute, 
and the Reinforced Concrete Practice Standing Committee of the Concrete Institute, 
presented at their 43rd Ordinary General Meeting, A Discussion folloived, of ivhich loe 
gi've a short summary. — ED, 



The follo\vinj4 Draft Report was presented after the Committee had held several 
me€tin<^s, and the Report is accompanied by the followins:^ recommendation : — 

''That the method of measurement as compiled by your representatives and as copy 
enclosed be adopted, signed by the signatory bodies, printed, registered at Stationers' 
Hall, and circulated among the Members of the Concrete Institute and of the Quantity 
Surveyors' Association." 

The Committee further recommended that in cases in which the working details 
are not complete engineers indicate for the guidance of their surveyors when preparing 
the quantities the thicknesses and weights of reinforcement as shown upon the 
drawings herewith. 

In submitting the report, Mr. S. Bylander (Vice-Chairman of the Reinforced 
Concrete Practice Standing Committee of the Concrete Institute) stated that in order 
to further the interest of reinforced concrete, simplification was necessary. The chief 
thing to be aimed at was to obtain a result, and the means to this end should be as 
simple as possible. If any part of the work entailed too much ex[)enso, it was their 
duty to reduce that amount of work so that only useful work would be necessary. 
Undoubtedly, when using a new malcrial, it afforded a better oj)jjortunitv to 
standardise. He thought the Institute had done well in asking the Ouantitv Surveyors' 
Association to join hands with them in trying to draw up something which would be 
of mutual advantage to professional engineers as well as to quantity surveyors. 

Th(; Quantity Surveyors' Association and the Concrete Institute would ultimately 
deci(l<- on the final form, after having heard the criticisms of that meeting. 

With referrnce to concrete generally, the Committee had, in carrying out the 
general idea of siinplifKalion, decided to adopt the foot as a unit, and not the yard, 
in order Ui a\'oid mistakes and unnecessary transference from one unit to another. 
It w<is certainly to the intere^t of every professional institution to work together in 
advancing the knowledge of the subject, and to nduce the amount of unnecessary 
cU-rical work in order thai ihey might concenlralc their minds u|)()n things that 
mattered, and by using one imit they could allain thai obj(ct. 

As to the ta!)ulated form which aciompanies ihe second rej)()rt, this was not 
intended as a bill of c)nantities to present to the buiNh r, j)ui onK' as a sheet in which 
th(' details of the quantities were given fiom ihe diawings, so that they could at once 
trace the quantities allow<(i for on the d. si^^n. lie tlicn <^ax(. ,-, dctaiU'd e.\j)lanati()n 
of the various headings comprised in the sluct. 

1-6 



», CCJjSl.v I PI (CTTOJa L 



STANDARD METHOD OF MEASUREMENT. 



REINFORCED CONCRETE. 

Suggested Method of Measurement. 

'I'hc \V(irk on cich lloor to he k(|)l separate, slatiiij^ the heif^hl from the ji^round 
to the se\-eial llooi^.. Keep concrete, centerinL,^ and reinforcement for each Hoor 
toi^ether. No i(inloi"ceni( nl to he deducted from the concrete; otherwise all measure- 
ments to he net unless stited, and notw ithsLindini^ an\ trade custom, to the contrary. 

CONCRETE. 

h'orxDA rioNs. |)er ft. cu. 

Basks to pillars, jxr ft. cu. 

Waii.s (.State each thickness separateh ), jxr ft. cu. 

TiLi-AKS (.State " a\-eraj4ini4 " or " rauLdnj^" from to "), per ft. cu. 

Floor .Slabs (Measure across heams; state each thickness separately), per ft. cu. 

Hi:\Ms (Measure helow sol'lh of lloor slal) ; state " averai^ini^ " or " rani^inj^ 

from ti) "), per ft. cu. 

RoOP'S (State slopes over 30 degrees sei)arateh- to allow for fdlin^ hetween double 
centering), per ft, cu. 

CiiASKS AND CiROOVK.s, Etc. (Whether cut or formed to be described), per ft. run. 
HoLE.s, Mortices, Etc. (To be described as either cut or formed, and size, dejjth, 
or thickness of concrete given), each. 

CENTERING. SHUTTERING, etc. 

Each variety of centering, shuttering, etc., to be measured separately. Poth 
sides of concrete requiring double centering to be measured. 

Foundations — Vertical, .splayed or circular, per sq. 

Walls — \'ertical, battering or circular on plan, per sq. 

1-^i.ooR .Slabs — Raking, circular on j)lan, or radiating (measure net between beams; 
the radiating centering to be described as including all cutting to radiations), per sq. 

Ditto, in S.mall Pieces, Landings, Etc., per ft. super. 

Pillars — All centering, etc., to include for strutting, timbering, wedges, etc.; 
square, circular, octagonal, or other shape, to include all cutting and waste; bases 
and caps for pillars, giving size, to be kept separate, per ft. super. 

Bea.ms — (To be measured as girth of beam from underside of floor slab onlv, 
'■ including all labours"; state if radiating or circular on jilan or elevation, including 
mitres), j)er ft. super. 

Roofs.- — Flat, raking, segmental, semicircular or elliptical (measure both sides 
if over 30 degrees slope), per sq. 

Return Edges of Openings in walls, floors, or roofs, per ft. run. 

Soffits of .Stairs — Raking, flewing or circular on plan (to be described as 
including cutting and waste), per sq. 

Mouldings — Over 12 ins. girth, per ft. super. 

Ditto — 12 ins. girth and under, per ft. run. 

Mitres, .Stopped Ends, Etc., each. 

Return Edges of Concrete Floors, .Strings and Risers of Stairs, per ft. run. 

Circular or Raking Cutting and Waste to be measured to all irregular surfaces 
of walls, floors and roofs, per ft, run. 

Key Blocks, Consoles, Etc., giving full size and description, each. 

Splays, Chamfers, Reb.^tes, Rounded Angles, Etc., to be described as including 
fillets and moulds, per ft. run. 

REINFORCEMENT. 

Ordinary steel bars from \ in. to 2 ins. diameter may be included under one 
heading (stating the diameters). Bars under \ in. and over 2 ins. in diameter to be 
kept separate. Bars over 30 ft. long to be kept separate. 

All w'ire ties (exclusive of helical or horizontal binding or stirrups) to be included 
in the description of the reinforcement. 

D 177 



STANDARD METHOD OF MEASUREMENT. 



ICDNCBETEl 



^ 



^sr-^/y^ 






^^-^ff/ <jff/ 



j?:Z/^^/-tr 



i^r-jwiot^ 



^<g'-^/^^/ 



^ 



g^^-^^^gg- , 



^ 



Off^doSafOQj^S^ 



PP/^'^'P 



,^0'.rer )i,^/-t^ 



.O'Zar 



2: 



9^/-^ 



„0:zer ^^^f-9 



V 



I 



^ 



•0 






'^ 






Q 






I 



•§« 




178 



y,CONMU>lKriONAl, 



STANDARD METHOD OF MEASUREMENT. 



The (.lilTcrtiit items of r( inforccnicnl lo he kept >(|).ir;itc as described for 
*' (\)iKM('te " and " CenterinjLi, Sluil teriiiLi, etc." 

SiKKi. Raks Slate " iiuludiiii^ all bends, hookeil ends, etc., and Jixin;^ at any 
Ie\('l, in an\' position," |)ei' ewt. 

SiiKiars \\n I>!\I)IN(. lloii/onlal oi- belieal, jxr cut. 

M i:mi\\()KI>: Ri.im ()U( i:.Nn:N i sup|)lied in sbeets oi- rolls to be measured " ik t 
{i.e., no allowance made in llie measurement for ]a|)s or for straight cuttinj^ and 
waste), including all labours for bendin<f, elc, per \(1. sujxr. 

Rakinj^' and ciri'ul.ar cuttini^ and waste 1o ditto, per ft. run. 

.1 draft report was also prrsculed by the Reinforced Concrete Practice Standing Com- 
mittee recommcndi)ig that a standard tabulated form for preparing quantities for 
reinforced cofjcrete work be adopted. Hie CoDiniittee subi)iilted a form witJi Jieadings 
for co)isideratioti and discussion. 

DISCUSSION. 

Mr. George Corderoy, Assoc. last. C.E., slated that with regard to reinforced concrete 
they were happily not hampered with any ancient customs of measurement. Nevertheless, he 
thought that if they left out any of the ancient practices in preparing a bill of quantities, unless 
they were careful to safeguard themselves in some way, they gave opportunities for claims for 
payment on the score of custom. He regretted that the Committee had not the full courage 
of their convictions to adhere to the foot unit for centering and shuttering for foundations and 
walls. There was really no merit in the term "square" as applied to a great many items of 
foundation work, and the term " foO't " was very often used for centering. He gathered that 
the guiding principle of the surveyors who had drafted the Report had been that which had 
practically governed the preparation of ordinary quantities, namely, that no manufacturinsJ 
labours were included, but only fixing labours. 

In conclusion, he moved that the first recommendation should read, " That the method of 
measurement as compiled by your representatives and as copy enclosed be recommended for 
adoption by surveyors practising in measuring, and quantity surveyors, signed by the signatory 
bodies," etc., thus making the resolution recommendatory and not mandatory. 

Mr. G. C. Workman agreed with Mr. Corderoy that it would have been better to have kept 
to the square foot in centering, shuttering, etc., for foundations and walls. He understood 
that the reason for the adoption of the square was that contractors were in the habit of buying 
their timber by the square. He thought that a medium might be found between the square and 
the square foot; the square was too large, and the square foot was too small. That would 
apply also to floor slabs, roofs and soffits of stairs. 

Mr. Alan Paull, F.S.I. , suggested that, as bases and caps for pillars were of various 
sizes, if kept separate, as recommended by the Committee, it would lead to a lengthening of 
the bill. He further suggested they should omit the words " giving size," and substitute " in 
so many," in connection with the measurements of pillars. He supported the Committee's 
adoption of the square as against the foot because it showed that a large quantity was being 
dealt with. 

Mr. Bylaader pointed out that it was only intended that the bases and shuttering should 
be kept sei)arate from the body of the column or shaft. 

Mr. F. B. Wentworth Shsilds, M.Inst.C.E., thought that it would be well to standardise 
as to whether the driving of piles should be charged as a separate item from the making of 
them. He noticed that the Committee had ingeniously got over the difficulty of having six 
different names for shuttering by inventing a new one. He suggested that, instead of coining 
a new word, which was alwav^s difficult to popularise, they should adopt the American term 
'' False Work," which covered all the Committee meant to convey. He inquirtJ whether it 
would not be well, when describing the floor slabs under centering and shuttering, to state that 
the price should include temporary props? 

Mr. P. F. Gleed, F.S.I. , thought that their object as surveyors in preparing bills of 
quantities was to give the contractor such information as would enable him readily to obtain 
a correct value of the contract to be executed, and they should do that irrespective of tht 
amount of trouble it caused themselves. He thought it ought to be cleared up in considering 
the suggestions before them — whether the Concrete Institute represented professional engineers 
or (ontracting engineers. 

I) 2 179 



TANDARD METHOD OF MEASUREMENT. [CONCRETE] 

Mr. W. E. Davis felt that there was a good deal in the suggestion that the use of the 
square as a unit in regard to shuttering for foiuidations, vertical, splayed or circular, was 
rather a large order. The question of pile driving was a most complicated matter for a 
quantity surve\or to deal with, and he was sorry that the Committee had not tackled it. He 
thought that the diagram which the Committee had prepared would be of immense value to 
quantity surveyors. 

Mr. G. At. Nicholson, F.S.I., seconded IMr. Corderoy's amendment. He agreed with Mr. 
Davis that it would be a benefit if some suggestion were given for dealing with concrete piles, 
as the latter could hardly be considered the same as pillars. It would be an improvement to 
the report if they could have some guide as to the measurement of concrete piles and the 
driving of them. 

Mr. A/baa H. Scott, M S.A., who had been prevented from attending the 
deliberations of the Committee, was sorry to find himself at cross-purposes with 
soaie of the recommendations. He had yet to learn that it was only engineers who had 
to deal with designs for reinforced concrete. He ventured to suggest that, in dealing with 
concrete roofs, no district surveyor would allow concrete to be worked with only single center- 
ing for a slope of over 30 deg. He had never carried out work of this kind with more than 
a 25 deg. slope, and too much risk was being run at that ; 18 deg., he thought, was the limit. 
It was a pity that they had not asked the opinion of the London Master Builders' Association 
and the R.I.B.A. before they issued the report. He suggested that in the L.C.C. Regulations 
there were a lot of good definitions for the various terms employed in the work, especially for 
centering, and he thought that much of the discussion that evening would have been avoided 
if the Committee had adopted the terms used in the L.C.C. definitions. 

Mr. R. Graham Keevill, A.M.IMech.B., suggested that pile work should be classified 
under two heads, cutting and driving, and moulding. Included in the price for driving should 
be given the cost of scantling. Cylinder work did not appear to have been dealt with, and 
perhaps the Committee, in elaborating their report, would deal with the question. He 
presumed that the form given would take into account the beamless floor, which seemed to be 
a thing of the future. Although America appeared to have a monopoly of it at the present 
time, there was a possibility of this becoming a standard thing in this country in the future. 

Mr. E. Fiander Etchells, F.Pbys.Soc. (Chairman of the Science Standinig Committee, 
C.I.), said their one aim was simplicit^^ They would always have difficulties until it was 
made clear whether form work included strutting, and whether centering included sheeting. 
The\' were building up a terminology for a comparatively new subject, and it was their duty 
to buila foundations in such a manner that those who came after them would be able to take 
them down. 

Centering, using the word in its widest sense, comprised three kinds of timber — sheeting, 
battens, and strutting, and they wanted some term to cover the three. After an exhaustive 
investigation of all available te.xt-books, it was found that the majority of persons used the 
term centering. He thought that there was considerable misapprehension as to the derivation 
of the word " centering," many people being of opinion that it was an Americanism. The 
word " center " was derived from an old French word, meaning the timber work used for 
supporting a structure during its erection. It so happened that structures which most required 
supx)ort during erection were arches, some of which had one centre and others three. 

The point had been raised as to whether the members of that Institute were professional 
engineers or contracting engineers. It was rather a difficult question to answer, but they had 
examined themselves and found that five-sixths of them were called professional engineers, and 
one-sixth specialist engineers. 

Whether they decided in favour of the term "' forin work" or "centering," it would be 
advisable to ask the Local Government Hoard to adoj)! that word, as the Regulations had now 
left the hands of the County Council, and were now under the consideration of the Board. 

Although they were a sjjecialist society, he thought it was advisable that their report 
should be recommendatory rather than mandatory, because they were the youngest specialist 
institution and ought not to dictate to older societies. It was a (piestion as to whether anyone 
was competent to lay down a rule for another autliorily in matters where i)ublic interests were 
not concerned; moreover, as there was no penalty aftaclicil, they could not enforce regulations 
which they sought to imiK>se. 

Mr. Perclval M. Fraser, A.RIBA., agreed with the observations of Mr. Alban Scott. 
He knew what the <>i)inion <>\ llic |{uilders' Association would be. An expert estimating clerk 
would imt his i)en through all this and a^k for lliicc llc-nis. He strongly deprecated the 
reduction of the units from yards cube to feet cube. \vlii(Ii entailed very great labour and 
greater risk of error. It was ridiculous to measure pile^ so inu( h per yard cube for the concrete, 
including driving. 
iHo 



y, CONM U'lliriONAl, 
« V tN( il N Kl klNd -- 



STANDARD METHOD OF MEASUREMENT. 



Atr. T. J. Carlcss. I'icsidcnl ol ilu' (.)ii.inlit\' Survcxors' Ass<)( iiilion, had /,'rt;it pleasure 
m Mipportiii},' (lie rc'pori of the Joint (ommiltee, and ihouKht llial ilir l'ri'si<lenl of the Concrete 
Institute would be cpiite willing to accept Mr. Corderoy's suK/^jeslion. Personalis', he was 
not alt()f,'ether in accord with the ojjinion. of the majority of the nuMuhers of the Council of 
his Associati<Mi. lie did not see the necessity for keeijin^ the work on each floor sejjarate ; 
builders wluwn he had consulted did not want it : the\ niij^dil just as well keep the bri(kwf»rk 
to ever> floor se|)arate. As an individual, he ihou/^ht that the same unit was not a|)plicable 
for all classes of work, although his Institute had af^reed to the foot cube unit. The unit 
should suit the work, and the work should not be made to conform to the unit. 

Mr. A. a. Cross, F.S.I., said he could not a/,'ree with Mr. Workman's suRgeslion, because, 
b>- using a square the tlecimal unit was maintained, but the obje<tion of having loo many 
hgures for one column was overcome. 

He agreed wnth Mr. Alan Paull that the words, " giving sizes," in connection with bases 
and caps for pillars, was superfluous. 

Ill reply to a question of Mr. deed's, he thought that keeping the work on each floor 
sejiarate cleared up the cpiestion of hoisting, and did not involve the surveyor in very mui h 
additional w'ork. 

As to Mr. Davis's objection to the measurement of floors by the foot cube, Mr. Cross said 
that most of the Committee were of the same opinion, but they eventually came to the conclu- 
sion that one unit for the whole w-as desirable, and any other unit for beams and pillars 
seemed to be out of the question- 
Mr. Alban Scott had asked that the R.I.B.A. should be consulted. They had consulted 
the R.I.B.A., and that body had no opinion on the question of a standard system of 
measurement. 

Mr. Cross concluded by expressing the hope that the final report of the Committee, after 
effect had been given to the various suggestions made that night, would be adopted. 



1«I 



REINFORCED CONCRETE ELECTRIC STATION. 



[CQNCBETEJ 

=0 




Fig. 1. 



Reinforced Concrete Roof of Power House 
in course of construction. 



REINFORCED 
CONCRETE 
AT THE 
CENTRAL ARNO 
HYDRO- 
ELECTRIC 
STATION, 
CEDEGOLO, 
ITALY. 



An interesting instance of reinforced concrete -work in connection -with a hydro-electric 
station is that of the Central Arno Station at Cedegolo, erected for Messrs, Adamello, 
There are various features in this -work ivhich are ivorthy of study. The ivork ivas carried 
out to the designs and under the supervision of Messrs. Damioli Bros., of Milan, to ivhom 
'we are indebted for our particulars and illustrations. — ED. 



There is some interesting reinforced concrete construction in connection with 
the hvdro-electric station recently erected in Italy and known as the Central 
Arno Station, and although the methods of design are somewhat different from 
those employed in this country, there are several points worthy of notice, 
particularly so as regards the design of the retaining wall or dam surrounding 
the large reservoir or basin from which the hydraulic power is derived. 

The building forming the powder house is over 200 ft. long and about 
4S ft. wide, and is a one-story building with outer walls of brick and stone 
roofed with reinforced concrete arched trusses. These trusses have 
principal rafters 10 in. })y 5 in. reinforced with four bars in the lower 
surface and these are inclined in the ordinary way and support panels 
of hollow bricks which are put together with a keyed joint and to which the 
tiling is attached. A horizontal tie beam, 10 in. by 8 in., reinforced with four 
rods in the louer surface and two in the upper, connects the ends of the 
rafters, and in addition to this a curved beam is formed which connects with 
the same points and rises about S ft. 6 in. above the tie beam. This curved 
beam is 12 in. deep b\ 5 in. wide and is reinforced with two bars in ()()th upper 
and lower surfaces, w liihr ihe ceiling over the apartment is formed at this level 
and follows the same cur\c, this being also (-onstructed with hollow bricks 
ha\ing a ke)cd joint. .\n inclined strut coiniecis the rafters and tie beams at 
the junction of the lonner with the arched beams and this is 8 in. l)y ^ in. 
with one rod in e;i( h corner. The hearing for the trusses is provided by the 
mass of reinforced conciele hirniid ;il the junction with the wall, where the 
eaves i)roject ;i (lis!;Mi'( of ;ih(;ut j;5 in. from t h,e I'aee of the wall, tiiis portinii 
being also in reinloiced ( oncrete, the bars being continued outward from the tie 
beams and hooked down. X'arious stirrups and ties are provided al intervals to 



all the members and the bars in the rafters are 
182 



< i.'mked uj) where j^assing over 



« V F.NfilNKKRINti — . 



REINFORCh:i) CONCRHTB ELECTRIC STATION. 



tin- strut to proxicli' cout iiuiit \ . Sonu" idi-.i ol the iii;i«^ nil lulc ol the work Jind 
tin- liinhiM-itii^- ri'(|uirt'(l c:in ])c |L;atlu'ic(l Ironi tlu- |)h()t()^r.'i|)Iiic \ic\\s in F/.tf-v. 
1 ;iiul J, \\lii(-h wfic taken diiiiui^ j)i()i4 1't'ss, wliiK' the ixlciioi- \ icw of the 
conipKlcd hiiiI(HiiL; is sliown in h'tt^. .\. 




Fig. 2. Power House in course of construction. 
The Central Arno Hvdro-Electric Station at Ckdegolo, Italy. 



The water basin has an irregular-shaped plan, with a maximum length of 
about 190 ft. and a maximum width of about 150 ft., in addition to the valve 
chambers, etc., which are constructed at one end. The total height of the dam 
surrounding the basin is about 25 ft., and it is not constructed in the usual 
manner with an ordinary single wall, but is built with inner and outer divisions, 
which are connected by hoiizontal and vertical slabs and beams, as shown m 

183 



REINFORCED CONCRETE ELECTRIC STATION. iCONCBET^ 



r\ 




ViK- 3. '1 I.I.. -.'- 1 • heel ion >a 1:- mi' n • ■! ' > u- ictc Dam. 
TiiK Cknirai. Akno Hydro-Ei.kctric Station at Ckukgoi.o, Italy. 



1S4 



/v-S^rffSg :^ia Rhinforchd concreth electric station. 



tlu' (Iniwin- in F/V. ;,. rii(> (.utsidc width ..f thrsc lu,, dixisioiis is .,l„,ul if, fi., 
.111(1 llir thirkiuss ;,i ilic hasr ..f .arli division is u in., will, ;, ,vd„. li,.n to hin' 
lliick .11 tlu- top. R(>inr()i(vm.nt is provided in both inn-.r ;,nd o.itcr sinr;.<i-s 




\vi:h stirrups ()r links conncctino- the two sets of rods; wiiile the space between 
the two divisions is divided up into three compartments by the horizontal 
divisions, and the foundation is formed by a connecting- slab lo in. thick and 
beams i6 in. deep, coincident with the vertical stiffeninp- transverse walls. 



i8; 



REINFORCED CONCRETE ELECTRIC STATION. 



[CQNCBETEJ 




186 



:^ 



r jN Cr;»N5TVi;tT10NAl 
LglF-NrilTMLKPIN( 



m H'ilNFURCnn CONCRETE ELECTRIC STATION. 




REINFORCED CONCRETE ELECTRIC STATION. [CQNCBETH 

The horizontal dixisions arc constructed with rei .forced slabs 4 in. thick and 
reinforced concrete beams 10 in. thick, the junction of the slai3 and wall being- 
streng-thcned by forming- haunches which extend down to a level with tiie inside 
of the beams. The vertical division walls, which also serve to tie the outside 
walls together, are spaced at intervals of about 10 ft. 6 in., and semi-circular 
headed opening-s are formed in these to connect the whole of the compartments 
and allow the water to How through. The interior is communicated with the 
basin itself, and consequently the whole of the space between the inner and 
outer walls of the dam is filled with water, and the weight of this water is 
added to the weight of the dam itself, and serves the purpose of increasing 
the resisting moment of the whole structure. It is claimed that a dam of this 
design can safely retain a volume of 15 per cent, more water than a masonry 
dam occupying the same space, and it certainly forms an efficient and unique 
example of construction of its kind. The disposition of the reinforcement 
generally can be gathered from the drawing, and need not be further described 
here. A view of the work during construction can be seen in Fig. 5, this 
showing the two division walls nearly complete and the interior of the basin ; 
and the finished basin is shown in Fig. 6, with the water filled into same. 
Some idea of the plan can also be gathered from this photograph, and the 
valve chambers can be seen in the distance. The top of the wall is filled in 
and forms a convenient walking way around the basin. 

The example is worthy of study by engineers, as it exhibits a thoroughness 
of design to suit the special requirements of the case which is creditaiJie. 



188 



J, tONMUtHTIONAi: 



THE HElMIiACIl SVi^TEM. 




THE HEIMBACH SYSTEM OF 
COMBINED WOOD AND RE- 
INFORCED CONCRETE PILES 
AND OF LENGTHENING 
WOODEN PILES. 



By PROF. DR. SCHONHOFER. Brunswick. 

This fourn^l frequently re'vieius interesting technical information as to neiv iniientions, 
and the information betna presented as a rule by the in-ventor or his agents is necessarily 
ex parte and frequently of a debatable character. It is extremely difficult, in such 
statements that are presented, for us to draw the line as to ivhere commercial optimism 
ends and general^ technical interest commences. In the following article, presented to us 
bv Professor Sch'onhofer, of Brunswick, and dealing 'with an Austrian in'vention, a notable 
instance is presented ivhere we think the scientific aspect claims attention, and although 
some of the statements contained in this article are not only ex parte but 'ver^ contro'versial, 
ive ha've published this contribution as one that may lead to discussion in our columns. — ED. 



The wooden pile, used for many centuries, has been largely replaced in recent 
times by the reinforced concrete pile. Reinforced concrete piles are every- 
where more ad\-antageous — where wooden piles would be destroyed by water, 
or where, <:)n account of the great lengths required, they would be too costly 
or unobtainable. 







Figs. 1 and 2. Figs. 3 and 4. 

Showing Method of Constructing Piles. 

Mr. Heimbach, of Bregenz, Austria, has ingeniously succeeded, first in 
combining the wood and reinforced concrete pile, and next in rigidly 
uniting two or more wooden piles. In this way a combined pile has been 
constructed, uniting the advantages of both systems, and independent of the 
depth of the ground water; whilst, lastly, the difficult problem of the lengthen- 

189 



PROF. DR. SCHONHOFER. 



[CONCBETEJ 



in^^ of i1k' wooden pik' has been solved, so that wooden piles may be obtained 
of any length. 

The combined pile is prepared as follows : A wooden pile, provided with a 
broad ring- at the head (Fig. i) is driven in the ordinary w'ay until the head is 
about a metre above the surface. The ring is then removed and replaced by 
a steel tube, S, made conical below, and forced over the 
cylindrical end of the pile. A steel annular wedge with 
radial ribs {Fig. 5) is then placed on the pile and driven 
home. This expands the upper part of the pile until it 
makes a firm and watertight joint with the conical head. 
The steel tube is strengthened by one or more protecting 
rings, R. Lastly, the steel reinforcement is placed in the 
tube, which is then filled with concrete, E. If the thickness 
of the tube be suITicient, special reinforcement may be 
dispensed with. 

In place of the annular wedge a conical w^edge with radial ribs, K', may 
be used {Fig. 2). Also a cylindrical steel tube may be used in place of a conical 
one, but in that case the protecting rings must be somewhat thicker {Fig. 3). 

A wooden pile is lengthened by using, in place of the simple conical tube, 
one with two conical ends, placed over the top of the pile {Fig. 4). A double 




Fig. 5. 

Annular Wedge with 

Radial Ribs. 




1M(;. (). I'l.AN 01 Buil.DINd Al J.INUAt! 



annular wedge K", is then i)hi((Ml on tlu; wood and the second pile, H', with 
a cylindrical vn(\, is then driven into the open end of the tube. 'Ihe ramming 
causes the wedge to ('nt<:r the ends of bolli the wooden piles, and by fitting 
tightly into the tubes to make a liglit joint. 

The Heimbach compound piks and ni(lh<Kl oi lengthening have been 



iqo 






THE H EI M BACH SYSTEM. 




(.■in|)li)\ t (1 ill inanv cunslruclions. TIic firm '>(" Ilciinl);i(li .-iiid Scliiu-idLT, ol 
Hrt'i^i'ii/ ;in(i l/ind.iii, Iki\i (.■iiij)li)\ id lliciii will) success in in;iny huildinj^s. 
Tliis rinn owns I lie piitcnls in all countries. I'i^. ') slious tlic plan of such a 
])uil(lins4' at Lindau. Fii:; H is a j^cncral xicw, and I'i^. 7 shows a detail of 
tlu' const ruction. I he two new .systems ol j)ilini4' were also exhihiled at the 
Internalional Huildini; h.xhihilion in Leiji/.ii^-, attractinj^' much attention and 
obtaininj^- the i^old medal ol 
the Cily of Lcipzii;. 

The combined wtxjd 
and reinforced concrete pile 
gives all the advantages of 
a deep foundation, especi- 
ally those of avoiding deep 
excavations and costly 
dams. The manufacture is 
simple, and special pre- 
liminary work is unneces- 
sary. The costly equip- 
ment for the bending- of 
reinforcingf rods, erection of 
shuttering, etc., necessary 
for reinforced concrete 
piles, is avoided. Ram- 
ming may be begun at once, 
and the operation proceeds 
rapidly and continuously, 

using the ordinary pile-rammer. The special rams and frames used for rein- 
forced concrete piles are not required. This is particularly of advantage where 
the earth is very soft, as the great weight of special pile-rammers is then a 
disadvantage. 

The vibration in ramming^ is not excessive, which is an advantage where 
the work is near to dwelling-houses or structures the safety of which is 
endangered. 

The combined wood and reinforced concrete pile is independent of the 
level of water or ground-wat^r, provided that the wooden part is at a sufficient 
depth. It is also of advantage in soils or waters which destroy concrete. This 
is the case with boggy and peaty soils, containing humic acids, with waters 
containing calcium sulphate or magnesium salts, sea water, or industrial waste 
waters containing acids. Wood is not attacked by any of these substances, 
and the concrete is protected by the steel tube, and, on account of the water- 
tight connection, cannot be reached by water. The steel tube may be pro- 
tected by paint or by a metallic coating. 

The load-carrying power of the combined pile is great, and especially 
in soft, muddy or peaty ground is large in comparison with reinforced concrete 
piles, as the wooden part becomes tightly fixed in the earth and increases in 
load-carr\ing powers with time. 

The combined pile is specially suited to the foundations of reinforced 

191 



Fig. 7. Showing Detail of Construction. 



PROF. DR. SCHUNHOFER. 



ICQNCKETEJ 



concrete buildings, as the solt'-plate of such buiidin^^s is naturally much more 
easily attached to the reinforced concrete part of such piles than to the heads 
of ordinary wooden piles. It is also suited to marine work, as the wood 
embedded in the earth is protected from boring molluscs, whilst the concrete 
is protected from sea water. 




Fig. 8. General Vikw of Building at Lindau. 

This system oi piling is cheap, as the embedded portion is of wood, and 
only the comparatively short upper part is of the more costly reinforced 
concrete. 

The Heimbach method of lengthening ])iles has also many advantages, 
being axailabic where, <m account of the length required, single wooden piles 
\\<;uld b(^ too costly or even unobtainable. This is particularly the case with 
marine landing stages, where wcxxlen |)il('s are necessary on account of their 
elasticity, whilst they ha\e also to be of gieat length. The union of the 
two j)iles is not only rigid, but hi^^hly elastic, so that the combined pile is 
fully equivalent to a single pile. 



192 



' j,lONMkMK-riONAl. 



I^WCTORY CONSTJWCTION. 




j J8|i1'|l!lfiii!liMiillillillli11llll'^MIll)llill!l!l^ 



RECENT VIEWS ON 

CONCRETE AND REIN. 

' FORCED CONCRETE. 



THE CONCRETE INSTITUTE. 



It is our intention to publish the Papers and Discussions presented before Technical 
Societies on matters relating to Concrete and Reinforced Concrete in a concise form, and 
in such a manner as to be easily a'vailable for reference purposes. 

The method loe are adopting, of di'viding the subjects into sections, is, we belie've, a 
neti) departure. — ED. 



THE CONCRETE INSTITUTE. 

FACTORY CONSTRUCTION. 

By PERCIVAL M. FRASER, A.R.I. B.A. 

The folloiving is an abstract from a paper read at the Forty-second Ordinary General 
Meeting of the Concrete Institute. The lecturer illustrated his paper by numerous 
interesting slides. 

INTRODUCTION. 

It is now generally recognised that a well-equipped series of shops is an absolutely 
essential factor in a successful industrial concern. 

It cannot be denied that English factory buildings, whether in reinforced concrete 
or otherwise, cannot bear comparison with similar buildings abroad, especially in 
America. That English factory buildings, even with the most enterprising and 
successful firms, are often disgraceful, no one who has had any experience in our great 
manufacturing centres can deny. 

The attempted adaptation of groups of buildings to a use foreign to that for which 
thev were designed is one explanation of the grotesque jumble of nondescript buildings 
dignified by the name of industrial buildings which we so often see. 

It is also true that in the majority of cases economy could have been effected had 
the old buildings been scrapped and an entirely new series of buildings erected. I 
seriously suggest that the English factory owner requires educating in such matters as 
this, and that he has a great deal to learn from the United States on such points. 

The relations of the architect and the engineer who is dealing with the lay-out of 
the plan or who is running the process of manufacture should be very close. 

Some of the reinforced concrete specialists make a point of preparing complete 
designs for factories and other buildings, concerning which they can have absolutely 
no experience or knowledge, and this is a further prolific source of ill-designed and 
inefticient factory premises. 

There is a great deal that is incongruous in our industrial works. A typical English 
power plant represents the finest product of human workmanship, and the employees, 
from the chief engineer to the humblest stoker, take a pride in keeping it at its highest 
jMtch of eflficiency and scrupulously clean, for to their mechanical minds it is a thing of 
beauty ; but this is ordinarily housed without scruple in a corrugated iron building, 
which is not only an eyesore but totally incapable of efficiently protecting the expensive 
machinery it contains. 

NOTES ON THE DESIGN OF INDUSTRIAL BUILDINGS. 

The governing principle in the design of industrial works is to provide efficient 
buildings at the lowest cost. A certain operation takes place in each department, and 

E - 193 



THE CONCRETE INSTITUTE. (CDNOBETEl 



these processes are components of the finished article for the manufacture of whidi the 
buildings are erected. Each building unit, therefore, must be designed to allow its 
particular j)rocess to be carried out under the best conditions and without restrictions, 
and the buildings as a whole must be schemed to allow the various processes to pass 
through them in the most direct manner without loss of time or waste in any shape or 
form. The difficulties and restrictions of a building site must be courageously dealt 
with, and are frequently put to valuable use; such as, for instance, difficulties in the 
levels of a building site may be frequently utilised to convey the material by gravitation 
through the various departments and thus reduce handling and power consumption, 
and again will often enable loading stages to be formed at convenient heights. 

The effect of well-constructed, light, and healthy buildings on the health and spirits 
of the workpeople is an important factor. 

Among the questions which frequently come before an architect in designing 
industrial buildings is the following : Whether the building as a whole should be one 
storv or more in height. Unless the foundations are likely to prove abnormally 
expensive it will generally be found that the one-story building can be constructed the 
more cheaply. 

A second important detail which practically always arises is the question of 
eliminating columns or reducing their number and planning their positions to the best 
effect. 

Other questions which must infallibly arise are the nature of the lighting, which 
must, for many manufactures, be from the roof. In two-story buildings the width of 
the building is determined hereby, but it is an advantage to make the upper floor with 
roof light. Too much daylight, unlike artificial light, cannot be provided, but the 
increase of window space will add to cost and complicate heating and ventilation. 
The north or sawtooth roof is always an advantage, but is not always worth the expense, 
costing as it does lo per cent, more than an ordinary pitched roof in steel, or 20 per 
cent, more than a flat roof in reinforced concrete. 

With regard to the clear height of workrooms, a margin should be allowed over 
the bare necessity. 

The number and disposition of floor beams is often dictated by the needs of 
economical design, but frequently one has to provide floorslabs free from beams to 
increase headroom or for other reasons. 

In dealing with the advantages and disadvantages of reinforced concrete for 
factorv construction in comparison with the prevailing methods of construction, the 
following points must be considered. 

There are, of course, three attributes of every marketable commodity — namely, 
goodness, badness, and indifference. A casual examination will show that reinforced 
concrete will be adaptable and suitable for factory construction. We have, therefore, 
to weigh the special advantages that it possesses with the disadvantages, and decide 
whether the advantages are such that it is as good as other methods of construction 
at the same or less cost. 

Thf* serious comjjetitors of reinforced concrete which are at present before the 
building world arc as follows : — 

Brick, steel and cast-iron, wood, sheet-iron and metal lathing and plastering, 
tiling, tcrra-cotta or similar slabbing and casing, and a number of patent forms of 
construction too numerous to mention and most diflicult to classify, most of which, 
however, come within the scope of reinforc^'d concrete in one or more respects. 

It is exceedingly difficult, if not impossible, to definitely pronounce on the com- 
|)arativc ccf)nomifs of the foregoing materials, and we can onlv take specific instances 
and endeavour to generalise from tFiese. I am able to give a case where competitive 
prices were obtained for a building, which is of a fair size, straightforward, and a 
reallv useful one for this comparison. In this case alternative^ schemes were prepared 
in the fullest detail and ( onifxtitive prices obtained. The results were as follows : — 

1. l''or a steel-frame building with biick walls, corrugated iron roof (two- 
thirds north light), wood joists and boards on steel bearers to galleries, and patent 
glazing to roofs, the cost was 100 pei- cent. 

2. I^'or a reinforced concrete building with roofs as last, ()2 per cent. 

3. As last, but with concrete roofs, pari flat, part with north lant(>rn lights, 
but with })rick panel walls .S«i per cent. 

•94 



r »,cx>Nyrk'uc-rioNAL l FACTORY CONSTRUCTION. 

4. As No. I, l)ul willi coi I iil;;iI((1 iioii \\;ills, S() pci- (■ciit. 
:;. \\lu)ll\ ill I tiiilorcfd concrclc, SS per cciil. 
The luiiklint; was ;uMuaIl\ cariiccl out in reinforced conncle, including the gutters, 
doAii i)ipis, roofs, walls, foundations, and ev<'rv detail where it was possible for this 
material to he used, in this ease iheic were no special cii ( innstances whatsoever in 
favtnir of reinforced concrete; indeed, the question of tile supj)ly of a^f^re^ate was a 
veiy ilitVicult one, as it had to be broui^ht from twenty-five to thirty miles by rail. The 
forej^oini^ lij^ures will apply to all cases of ordinary buildinj^s costing more than, say, 
/,2,ooo. A i)uildini.; of less I'osl will, i^enerall\' sjK-akin};, in: found cheaper in some otlier 
h)rm of construction, and walls will nearly always be found cheaper in brick panels 
than in concMcte slabs. 

MA/NTENANCE. 

The freedom of concrete from deterioration permits of savings in maintenance 
charges. These are exceedingly ^reat in large series of factory buildinj^s, and can never 
be shown on pa|)er. Maintenance means more than merely i^uardinj.^ aj^ainsl the ravages 
of time. The necessit\ for maintenance implies decay; the maintenance costs are a 
d(\ad loss, and maintenance is in itself a thankless job owing to the fact that it is 
simj)lv patched-uj) work, nu'rely staving off the inevitable, which every year becomes at 
once more onerous and more useless. 

Considering the claims of reinforced concrete, without wishing to be unduly 
enthusiastic, it may be reasonably asserted that, after a lengthy trial and the closest 
scrutinv of our chemists, architects, engineers, and constructors, reinforced concrete is, 
practicallv speaking, free from dej)reciation if constructed according to the latest 
approved practice. 

Concrete constructions carried out during the Roman Empire are completely sound 
to-dav after a period of two thousand years entirely without maintenance. As regards 
thoroughness of construction and the quality of materials, the Roman constructions 
cannot* compare with the modern. This simple truth needs to be emphasised because 
the public are apt to draw odious comparisons between the Pyramids of Egypt and the 
modern suburban villa, without reflecting that the comparison is wholly unjust and 
grotesque. 

Even with rigid economv factory construction in concrete is, if conscientiously 
carried out, better constructed to-day, and therefore more permanent than any work 
constructed by the ancients. 

In reinforced concrete we have found one of the few suitable materials for the 
prevailing climate of Northern Europe. 

FIRE-RESISTING PROPERTIES. 

The fire-resisting properties of various forms of construction are of paramount 
importance in factory buildings. The effect of fire-resisting construction in reducing 
insurance premiums is but a small matter compared with the damage which ensues 
to a business owing to the extreme dislocation caused by a tire, which no insurance can 
ever cover; for we have to consider the financial loss in the shape of buildings, plant, 
and machinerv ruined, the destruction of office documents which cannot be replaced, 
and the permanent loss of many skilled workmen who are thrown temporally out of 
work, and the occasional terrible loss of life. The output of a firm is, moreover, 
temporarilv paralvsed, the normal trend of business is disorganised for a considerable 
period, and the eventual effect is that the insurance company will not reinsure at the 
same rates. 

Timber construction according to English methods is not only rapidly destroyed 
bv fire but acts as fuel. .Steel joists and cast-iron structural members are liable to 
immediate failure, and owing to the distortion in expansion and contraction will throw- 
down walls which with a timber construction would have remained sound and 
repairable after the fire. 

Steelwork can be effectivelv cased with resj)ect to stanchions and columns, but it 
cannot be said that a reallv efficient means of casing beams has yet been found, and in 
anv case such protection is expensive and clumsy. 

Nothing is, of course, fireproof, but we have to seek for the nearest approach to 
this ideal. Ordinarv reinforced concrete construction is as eflficient a fire resister as can 
be found. The metal is naturally guarded against by the concrete covering. There is 

E 2 195 



THE CONCRETE INSTITUTE. [CONQJETE) 

nothing combustible about tiic construction; it is not liable to exercise a dangerous 
thrusting or overturning action, even when heated and suddenly cooled. It is of course 
liable when quenched with a strong shower of cold water to have the covering of slabs 
and beams either l^ake off or disintegrate. It is rarely or never found that any of the 
concrete, beyond the covering to the reinforcement, suffers any irreparable damage. 
Any such covering can be broken away where loose and the building restored after 
the conflagration. It can therefore be fairly claimed that for factory construction which 
requires a high standard of fire resistance reinforced concrete can rival any other 
comparable method of construction. 

The fire insurance companies have been quick to recognise the use of reinforced 
concrete as a building material for factory construction. 

It will be noticed that their rules are very sound and practical. They are framed to 
be applied in an honest and liberal manner, and are altogether in great contrast to the 
usual official notices of this nature. The only criticism to be offered is, that although 
they allow floor slabs to be 5 in. thick, and roof slabs 3 in. thick, they ask for external 
wails 6 in., partition walls S in., and party walls 13 in. 

The Rules read as follows : — 

RULES 

AS TO ' 

FERRO-CO^XRETE OR REINFORCED CONCRETE CONSTRUCTION 
Issued by the Fire Office Committee. 
" Buildings constructed with concrete, reinforced in every part with embedded metal rods 
or bars spaced not more than 12 in. apart, securely connected ot overlapping at least 6 in. at 
all abutments and intersections, having also bands or bars across the thickness of the conicrete, 
may be deemed as Standard 11. Construction, provided they conform to the above rules for 
ordinary brick and steel construction, with the following modifications : — 

" Concrete may be composed of sand and gravel that will pass through a |-in. mesh, 
or of the other materials mentioned in the Rule (stone, brick or terra-cotta), but in any case 
the cement used must be Portland (equal to the British Standard Specification of December, 
1904), in the proportion of 6 cwt. o-f cement to each cubic yard of concrete. The Concrete 
must be thoroughly mixed both dry and wet, and must be rammed round the metalwork 
in position, every part of which must be completely enclosed with solid concrete. 

" No external wall to be less than 6 in. thick in any paxt, and no division wall less than 
8 in. No party wall to be less than 13 in. thick in an}- part, unless the adjoining building 
be of reinforced concrete construction in accordance with Standard Ia, Ib, or II., in which 
case 8 in. is allowed. 

" Flues may be built of reinforced concrete as described, not less than 4 in. thick, 
if lined throughout with fire-clay tubes not less than i^ in. thick. No timber or woodwork 
to be in contact with such flue. 

" Floors must be constructed of reinforced concrete as described, not less than 5 in. 
thick in any part without woodwork embedded therein, supported on beams and columns 
of similar reinforced concrete. 

" Roofs must be constructed in a similar manner to floors, the concrete in no part to be 
less than 3 in. thick. 

"All structural metalwork must be embedded in solid concrete, sO' that no part of any 
rod or bar shall be nearer the face of the concrete than doul^le its diameter ; such thickness 
of concrete musit be in no cas€ less than i in., ])ut need not be more than 2 in. 

" Enclosure to staircase and hoist, if of reinforced concrete as described, may be 
6 in. in thickness. 

" Fireproof compartments in connection with reinforced concrete structures must also 
be of reinforced concrete as described with walls not less than 8 in., and floors not less 
than 5 in. in thickness." 

// YGIKNIC PROPERTIES. 

T(j ((jmjdy will) th(! spirit (jf the ilome Oflicc rc(|uirements a constructional 
material for factory buildings should be sik li as will not absorb dust or dirt in an\' 
form, which can be cl(;an(td or kept clean with liltle elforl, and which offers a fairlv 
even surface. Th(! other tyfjes of factory construction -aw matnly of brick walls and 
wood and ste/;l-joist fioors, and steel or iron columns, <'ilh(T cased or unprotected. It 
cannot be said that reinforcx^d concret<' offers any extraordinary advantages over the 
materials named. It is certainly better than brickwcH'k ; and in order to comj)lv with 
the Home Office requirements it is more economical to lime-white than to ])aint, so 
that it may be considered to have an advantage over metal construction; "nd it is 

196 



i, coNyrpiK'noNAi^ 

AK-N(i1NKI,RIN(i '^. 



FACTORY CONSTRUCTION. 



uiidouhtcclh' nunc .KK-.tiitai^coiis to h.iNc laii^c lloor spans of concrrtc wilhoiit sulisidiary 
beams to obtain unbroken suifaces wbicb can be kept s('iuj>uloiisl\' clean and white and, 
incidentalK , w bii b rellect daybi^iit or aiiiriciai ilhiniination in a most elTicient manner. 
Iherelore, on I be whole, (Vom a bxi^ienic standjx)inl reinforced concrete has in the 
aggrej^ate (.|iiablie> whiib no olber material possesses in an equal degree. 

SAV/.Va /N SrACE. 

A further consideration which aj)plies mainly to warehouse buildings is the im- 
portance of affording the utmost llooi' spac(^ foi- the storage of goods. (Jonslruclion 
in London is exceeding!}' onerous in this resjxcl. Matters have been matle considerably 
easier by the steel-frame amendment of the London lUiilding Act, but it cannot be 
deni(^d that a considerable encroachment on lloor s])ace can be avoided by the use of 
reinforced concrete walls and supi)orts. 

The objection to reinforced concrete, as compared with steel and cast iron, in 
resi)ect to posts and columns is that the lloor sjjace occupied is considerably more. This 
is imdoubtedly the case, but, excej)ting in <'Xtreme circumstances, such as cotton or 
spinning mills, etc., the bulk of tlie concrete sujjport is not a serious objection. 

It should be remembered that if a steel stanchion is insulated against fire, it would 
be practically as great in sectional area as the concrete column. 

VIBRATION. 

An im})ortant consideration in all factories where machinery is em|:)loyed is the 
aggregate vibration, which is often very considerable. The nearest approach to such 
solidity is to construct factories of reinforced concrete, which, while being of mono- 
lithic construction and free from joints as ordinarily understood in building construction, 
is an effective absorber of vibration. With this in view the use of slender columns and 
comparativeh' narrow beams are to be deprecated. 

ADAPTABILITY. 

Perhaps the unique merit of reinforced concrete lies in its extraordinary adapt- 
ability. 'Inhere is no other building material which can be put to such extraordinarily 
diverse uses without unwarrantable eccentricity or expense. The value of a material 
which can be used for practically any purpose which may arise in the construction of the 
wide variety of buildings comprised in industrial works need hardly be dilated upon. 
The practical econom}' of such a material is also evident. Provided there are no 
insurmountable difficulties in getting on to the site steel rods, timber, gravel, and 
cement, we have at hand constituents which are capable of being moulded into any 
shape and resisting any strain and fulfil purposes which collectively would require the 
use of a large number of different materials. In the ingredients of reinforced concrete 
there is nothing w'hich cannot be readilv obtained in the most remote locality of the 
kingdom. In places ten or more miles from the nearest station, concrete w^ork always 
can comj:)ete in point of economv with anv other permanent form of construction, and 
wherever eccentric designs are to be carried out, a plastic material will always hold its 
own with a material which has to be wrought into shape. 

SPEED OF EXECUTION. 

Following on the adaptabilitv of reinforced concrete is the speed with which 
construction can go forward. If a contractor will lav down a well-considered and 
efficient plant, the rapidity with which a concrete job can go forward is remarkable. 
A larger number of workmen (mostly unskilled labour) can be usefully employed, and 
the building as a whole can be proceeded with uniformlv and in a manner which 
simplifies supervision. Should it be found desirable in a steel or iron construction to 
make alteration, time is lost in waiting for the various revised members to be delivered. 
With reinforced concrete such deviations can readily be made. 

Another point in favour of reinforced concrete against steel construction is that 
minute variations in stress can be met without undulv wasting material. 

ARTISTIC DESIGN. 

An objection which is often urged against concrete buildings, which does not apply 
to brickwork or the usual form of construction, is that it is by nature unsightly. If 
appearance is an object in a reinforced concrete building a very agreeable effect can be 

19: 



THE COSCRETE INSTITUTE. [CQNCEETEJ 

obtained bv perfectly leoitimate and economical means. Those interested in the possi- 
bilities of beauty in'reinforced concrete will do well to read Professor Beresford Pite's 
j)aper published in the " Transactions of ihc Institute," \ ol. III. 

ALTERAT/OXS TO FINISHED BUILDINGS. 

Another objection wiiich mav be held against reinforced concrete, especially for 
factory construction, is the great 'difficulty of making alterations which may be found 
necessary for various reasons such as an extension of business; but, assuming the 
building' has to be altered owing to circumstances which could not have been foreseen, 
such extensions and alterations are not impossible. Even if the expense is abnormal, 
it is one of those factors which every shrewd business man will be prepared for. 

In this connection the American will frequently tell you that if he builds a factory 
which will last without undue maintenance a couple of generations, he has more than 
done his duty bv r)osterity. We, personally, can hardly appreciate this point of view, 
but that the American is' certainly willing to raze to the ground any building which he 
considers is out of date is evidenc'ed bv the fact that one of the New York skyscrapers is 
being taken down because after a few years' existence it is found to be inconvenient. 

h cannot be denied that concrete, when it has settled down, is an exceedingly tough 
material, but the great strength to which this material attains should hardly be urged 
as an objection to its use. 

STRENGTH OF REINFORCED CONCRETE. 

The inherent strength of a building constructed entirely of reinforced concrete 
compares favourably with a building in any other material or combination of materials. 
Much has been said about the monolithic nature of reinforced concrete. We should not, 
however, forget that although a building is monolithic it is not monoferric (if such a 
word be allowable)— that is to say, that the steelwork consists of a multitude of small 
members held together by the concrete, but the external adhesion of concrete to steel- 
work makes a well-designed structure in practice a jointless one. Thus, an eccentric 
load on one portion of the building is disseminated over a large area of the surrounding 
structural members, and the local tendency of a building to spread or settle is resisted, 
not by the members locally affected but by the structure as a whole. In addition we 
have only to find the strength required in any portion and we can build up our structure 
to meet' the stresses induced, where such stresses occur, and without wasteful 
extravagance such as is often necessary in comj^romising with steel construction in 
certain peculiar conditions. 

BUILDING BY-LAWS. 

An objection to reinforced concrete construction, which will die out in course of time, 
is the antipatln- to a novel method of construction which is characteristic of the 
Englishman. I find, however, that individual building owners are easily converted if 
one honesth' points out to them the limitations and the advantages of concrete. The 
most formidable objection lies in the present attitude of the official world, who, in 
spite of the s[jlendid example which has been set by II.M. Office of Works in developing 
the use of this material in permanent and often monumental public buildings, have not 
been affected thereby to the extent of amending their by-laws. We have at present an 
eminently suitable material for the construction of |)ermanent buildings with which it is 
difficult \() sntisfv local authorities who, on llie other hand, will readily sanction a 
construction of light steel stanchions and roof trusses covered with corrugated sheeting. 
Fortunalelv, there appe.-irs to be nothing in local building by-laws which empowers 
the local survesor to rejeci buildings in reinforced concrete, and if an architect can 
Tjersuade his client lo go forward \\\h his building I do not belie\'e that he can be 
prevented. 

DAM!' KhSISlANCE. 

\ iiiinoi- advantage of reinfoicc-d cone i*le l)nildings is Ihat no d.'mip-j)roof course is 
needed, ;nid when one re.dises that 50 per c<rit. of the danii)-pro()f courses which are 
used with ihe apprr)val of lo(aI .lulhorities are worse ih.m us<i(ss this advantage is one 
which, though unimportant, is nevertheless real. 

A further minor ;idvanlag<' over steel construci ion is ihe obviating of nuisanci-s 

19H 



r /, ct::/N.vrpucTiONAii 



FACTORY CONSTRUCTION. 



raiiNcd in ctrl.iin |)r()C(ssis 1)\ londcns.it ion. ()fl(n condensation is un.'i\f)i(lal)lc, and 
the results of sMinie ar<' often dangerous, hainiful to the nianufacliin s, or ohjeclionahN- 
in other respei'ls. With reinforced concrete condensation is reduced to a mininiuni. 

/;('//.'/'(/' WOh'K 

In nian\ cases it is found convenient or desirable to construct the I)uildinj4 of units 
in a similar manner to ordinar\' steel construction, and this can be satisfactorily 
aicomplished in reinforcinl concrete. The chief advantaj^e of this is that a \irv'.\\ de.al of 
cenlrinj4 and struttinj^ is saved, and tlie work can be lianded over in a much shorter 
space of lime than if the concrete had to set in the usual way. At the same time, it 
must be admitted that this form of construction is in princi|)le open to objection, the 
monolithic nature of the huildinj^s is destroyed, and it is certainly not so economical 
as castinj^ the work in the ordinary manner. Its use is chiefly confined to floor slabs 
and walls, where it often offers very considerable advantai^es and ( conomy. 

FIXING PLANT. 

The one j^reat advanta^^e of structural steel in factory construction is the ease with 
which machinery can be fixed to the steel members. 'J'hat this use is often turned into 
abuse is beside the point, but en<^ineers state that they prefer steel to reinforced concrete 
for this reason. A little foresii^ht will enable an architect to meet this objection with 
satisfaction to the factory owner. 

The bulk of a concrete member is so comparatively large in relation to a rolled 
steel member of equivalent strength, that the resulting damage of cutting into such 
member is proportionately reduced. Comparing the members, the sectional areas of the 
steel joist and of the concrete beam are in the proportion of i to 7 for equivalent 
strengths. Therefore the concrete member will stand much more mutilation without 
jeopardising its strength than the steel joist. 

A simple means of providing for light fixings is obtained by casting a groove in the 
beams and columns so that a fixing can be obtained with the greatest ease without in 
anv way having to go into the concrete. For gas or water pipes and mains or cables of 
anv description, this fixing is very simple, and a good engineering job; again, the 
indiscriminate fixing of shafting to walls is accompanied with greater safety on rein- 
forced concrete slabs than on brickwork, which is liable to give along the joints, and 
the weight, of course, is not so evenly distributed. 

ROOF CONSTRUCTION. 

The low thermal conductivity of concrete gives it an advantage over the ordinary 
forms of roofing, apart from other considerations. The usual precautions taken are to 
construct a roof of timber with thick boarding overlaid with felt, upon which are placed 
battens and counter-battens and thick slating. This forms a fairly effective insulation, 
but the construction is at least as expensive as a concrete flat asphalted. For flat roofs 
and in all places where exposed to damp or water pressure concrete can be made, with 
due care, absolutely waterproof, and a very valuable and convenient arrangement which 
is now often adopted is to construct concrete roois with high parapet walls and utilise 
them for w^ater storage. This has a further advaniage that the water is generally at a 
convenient height to be drawn ofT under pressure. 

VARIOUS APPLICATIONS OF REINFORCED CONCRETE TO 
FACTORY CONSTRUCTION. 

ENGINE FOUNDATIONS. 

Engine foundations are often exceedingly complicated, and for this reason it is 
impossible to construct them with plain concrete, so that it is common and often 
necessary to emplov steel joists in order to avoid an excessive amount of concrete. It 
is obviously better to use a regular system of reinforcement wherever feasible. It 
enables the mass of concrete to be reduced to a minimum, and where, as is rnost 
frequently the case, the engine is to be set and a large proportion of concrete deposited 
after an interval, it is a great advantage to have some means of binding the mass of 
concrete together. 

199 



THE CONCRETE INSTITUTE. CDNCBET E] 

BOILER FOUNDATIONS. 

With regard to setting the boilers, practically the only efficient manner for the 
Lancashire type of boiler, which is perhaps most common in this country, and also for 
the water-tube boilers of ordinary type, is to construct a concrete raft so as to offer 
a clear working space for the boiler-setters, and for this purpose reinforced concrete 
construction is the best possible. Raft foundations are constructed as floor slabs 
supported on piles owing to the uncertain nature of the subsoil. It is particularly 
recommended that piles tor this purpose should be constructed of reinforced concrete, 
as it has frequently been found that where wooden piles are used the heat generated 
in certain portions of the flues is so great as to actually char aw^ay the head of the 
wooden pile and so cause settlement. The effect of heat on concrete is likely to cause 
failure unless a considerable period has been allowed to lapse after the construction 
before the heat is applied. In cases where a new boiler is installed and put into use 
immediately the setting is completed serious damage may be done to the concrete 
owing to the fact that it has not been allowed to dry off naturally. This damage w^ould, 
of course, accrue to plain as well as to reinforced concrete, and in the case of the 
former, where the practice is often to make the concrete slabs several feet in thickness, 
the resulting damage (where the subsoil is good) is not appreciable ; but in case of 
reinforced concrete, the slabs being thin, they may be entirely disintegrated. 

BOILER SHAFTS. 

It is only of recent years that chimney shafts have been constructed with true 
economy and efficiency in reinforced concrete, and all interested in this subject should 
read a paper delivered before the Institute by Mr. Matthews and published in the 
" Transactions," Vol. II., Part i. This session a further paper is announced dealing 
with steel and reinforced concrete chimneys. Experience has recently shown the com- 
parative cost of reinforced concrete chimneys, which, in one particular instance, show^ed 
a saving of 35 per cent, over a brick construction and a saving of 4 per cent, over steel- 
plate construction. 

An objection to concrete cliimneys is the unsightly aj)pearance, chiefly owing to the 
fact that it is unduly expensive to form a side taper, but this difficulty has been over- 
come in 2 simple and ingenious w^ay in some instances, and the system employed, so 
far from adding to the cost, is decidedly economical. In the cases in mind, the base 
of the chimney is quatrefoil in shape on j)lan, and the whole chimney constructed with 
one band of centring about 3 ft. high, which is raised, a batten taken out from each 
loop, and the centring correspondingly reduced in perimeter until it emerges into 
a circle at the summit of the shaft. The actual appearance is distinctly pleasing, and 
the insulation is good between the firebrick and the concrete. A certain amount of 
play is possible in expansion and contraction owing to the j^eculiar shape of the shaft, 
which is in effect equivalent to an expansion ])ij)e on steam tubing. 

SILOS AND BUNKERS. 

The construction of silos and bunkers, which have hitherto consisted of iron or 
steel, has been found in the last few years to be considerably cheaper and equally 
efficient in reinforced concrete, and some most imjjortant works have been constructed 
in this material. The grain silos which have been constructed in various parts of the 
world afford a few typical examjjles. 1 1 is useless to ])ress the claims of reinforced 
concrete in this conn<-ction, as so much work has l)een done in this country that it 
may be said that ste<'l (xr iron construction is now out of date. 

FOINDATIONS. 

Many serious (Jinicullics (onncclcd with f(jun<lalions on bad subsoils have been 
economically overromcj by a discreet use of leinforccd concret(^ It is a fact that a large 
percentage of our factcjries arc; situated by rivers, canals, etc., and for this reason the 
foundations are generally expensive. This «x|)(n(lil me on foundations frequently results 
in land otherwise chf-ay) proving in the end to be very expensive, as all such expcMiditure 
sh(Hdd properly be aclded to the cost cjf building land. 

There is practically no form of fonndalioii \\hi<Ii (annol he efficientlv constructed 
in reinforced concrete. A coininon, ertiiieDi, ;md ecoiioniicd form is the formation 

200 



^^^r^SlK^g I'^^CrOh'Y CONSTRUCTION. 



of a rail on which ronc-cntratcd ami disliihutcd loads of a huildinjf are equally S|)rf'ad, 
so that the unit load is rcducrtl cvcivwhcrc within the liniils of the hcariiij^ {•a|)acily 
of the soil. 

PiU's and shci^t piles in r(infor(((l coiutcIc have hern used in thousands, and its 
usf in ictainin^ walls has been able to oiler the most cxlraordinai y economies. 

liRIDGKS. 

1 1 is fi'eL]uentl\ found to be a threat conxcnieiice to connect various departments 
above i^round b\ means of j^anj^way bridj^es, and as the\ are nearly always inaccessii)le, 
it is i^enerallv better to construct these of material for which maintenance is reduced 
to a minimum. Hrid^es are usefid to cross public footways, and concrete has an 
advatUai>'e over brickwork or stone construction in ol)viatinif an excessive rise, and 
also in the saving of massive abutments. 

CONCLUSION. 

In conclusion, factory buildings are liable to be L^rossly overloaded, the costs are 
always reduced to the utmost farthint^, and the buildinjfs are not usually treated with 
such care as domestic or i)ublic buildin<^s, and are liable to be severely mutilated and 
subjected to the deleterious elTects of steam, vajiours, fumes, acids, oils, and undue 
vibration, etc. ; and, consequently, the factor of safety in design should never be 
reduced below four. It is also advisable to construct certain portions with even an 
increased factor, as, for instance, flat roofs which will with certainty be used for storage, 
and walls, beams, slabs, and columns, which are generally subjected to the suspension 
of shafting, motors, and other live loads without consideration of the |)uri)Ose for which 
they have been actually designed. 

In view of the enormous extent in which reinforced concrete has been used for 
buildings of this class during the past few years, it has been comparatively immune 
from failure. 

DISCUSSION. 

Mr. H. C. Johnson, of the Engineering Department of Universit}- College, Cork, forwarded 
a communication on the Paper, which was read, in the course v"f which he stated that it was 
wortii while to visit America in order properly to understand why the Americans were able to 
build in reinforced concrete more cheaply than could be done on this side of the Atlaptic. 
The reason that they were able to turn out more work per man was mainly due to new, well- 
lighted buildings, the great proportion of which were in reinforced concrete. It was possible 
in reinforced concrete construction to obtain a glass area equal to 80 per cent, of the total 
area of the building front, and run the glass to within three or four inches of the ceiling 
line. A large contract had been given to a reinforced concrete firm on their being able to prove 
that, including 12 years' maintenance, a concrete structure by them would cost less than if 
built in steelwork, the concrete first cost being higher. A saving of 15 per cent, on form work 
meant 5 per cent, more profit or less cost on the buildings. Another advantage of using 
reinforced concrete for buildings was that the greater part of the materials could be obtained 
locally, thereby keei)ing the money in the district. 

Mr. Leslie H. Allen ( Vberthaw Construction Co., Bostoai, Massachusetts, U.S.A.), also 
wrote that concrete was the only structural material which was made on the site of the buildings, 
and therefore there was a need of much more careful inspection of the work, and that the 
work itself should only be entrusted to those who had a thorough experience in the execution 
of it. Money was wasted or saved in reinforced concrete in the form work or centering, and 
everything that could be done to simplify that was of great advantage. The reduction of 
vibration was one of the points wdiich appealed to owners of buildings having high-speed 
machinery or having a rocking or reciprocating motion, which was distracting to the people in 
the building and caused a rapid deterioration of the structure and the machines. Although 
there had been several failures in the last two or three years in America, not one of them had 
bee;i after the building had been completed and taken over. They had all occurred in the 
course of construction, and they had been due to poor sand, faulty designing, or freezing the 
concrete before it set, overlapping greeii concrete, or removing the forms too soon, all these 
beiui,^ the results of inexperience rather than any inherent defect in the material. 

Mr. W. G. Perkins (District Surveyor for Holborn) thought it would have been more 
economical to have erected factory buildings to a height of three storeys. If brickwork were 
properly executed in Portland cement and solidly bedded up to the steel there was no danger 
of the steel rusting. That was the method prescribed by the Building Act, iSgg. If it were 

201 



THE COSCRETB INSTITUTE. ICQNCBETEJ 

not for the fact that the cement did protect the steel they should not be able to use reinforced 
concrete in their works to-day. Mr. Fraser, rather unfortunately, seemed to recommend that 
people should set by-laws aside, and put up reinforced concrete buildings whether the Local 
Authority liked it or not; but if they did not make their buildings in conformity with by- 
laws the Local Authority might proceed against them, and perhaps they might have an Order 
made for the demolition of the buildings after they were put up. 

Mr. Allan Graham, A.R.I.B.A., remarked that anyone looking at the average type of work 
that was erected in reinforced concrete was quite satisfied with the lines, but the features that 
they placed into the work, and the lack of artistic grace precluded it from an architect's 
point of view entirely. They must try and interest the architects in reinforced cO'nicrete work 
in order that they might attempt to give a little artistic effect to the designs. Some of the 
Ameri'an buildings, in South America especially, seemed to him to be much better designed. 
In centering he saw the only future to enable them to reduce the cost of reinforced concrete 
suffi(ientl\- that almost ever.\- factor)- in the country could be built of it. 

Mr. Ole Svendsen, M.Soc. Danish C.E., did not see why a well-built brick chimney should 
be better than a well-built conjcrete chimney. With regard to maintenance, he believed that 
concrete chimneys would easily be able to compete with brick chimneys. 

Mr. R. Graham Keevlll, A.M.l.Mech.E., regretted that it was the cheapest building that 
was freciuently put up. According to Mr. Eraser's paper, reinforced concrete had come out 
very favourably. The design of buiUlings was largely in the hands of specialist firms who were 
not at liberty to let the cost be known. If the cost of buildings were more generally known, 
that would be a large factor in helping forward the construction of concrete buildings, not 
only for factories, but for other purposes. 

Mrs. Margaret Williamson Morris, who had had very nearly 30 years' experience of work- 
shops and factories, api)ealt(l to architects for their assistance in combating dirt and darkness, 
and the want of air and light in such buildings as these, which contributed very largely to the 
spread of consumption amongst the working people. 

The President referred to the increase of strength in conc'rete spread over, say, ten years. 
A lot of experiments were being conducted as to the strengths of different cements with all 
degrees of grinding, and there was no doubt that with coarse grinding it took very much 
longer to obtain its ultimate strength than with the finely ground. It was very much better to 
construct a factory of entirely reinforced concrete in the country, as architectural features, as 
a rule, were aiot studied to such an extent as they were in towns. In towns it would be a 
mistake, o^^ing to the enormous amount of smoke, and the dirty appearance that it got, and 
the fact that the surface was alwa\s being attacked by the sulphuric anhydride in the 
atmosphere, which gradually caused it to crumble away. From the fire-resisting point of view, 
even if concrete cost more, the saving in premiums and insurance was very considerable. 
Vibration was very little felt in a reinforced concrete structure where it had been properly 
designed. In conclusion, the President referred to several serious cases of electrolysis which 
had occurred in the driving of piles in the I^ast End of London. 

MR. PERCIVAL ERASER'S REPLY. 

In reply, Mr. Fraser said that in America they had very many buildings in reinforced 
concrete, and although its use had been artificially stimulated by the fact that the local building 
authorities were not so " pig-headed " as they were in this coimtry, they could show more work 
and better work in this country than he had s.een at all evonts in the United States. He 
reiterated his opinion that factory buildings, generally speaking, were cheaper when con- 
structed in one storey than with two or more storeys. II is statement was founded on very 
many years' experience of factory <:onst ruction, and although he had been attacked from all 
quarters in regard to it, lie had heard no constructive criticisms, merely statements that he was 
wrong. He was careful in his i)aper not to mention district surveyors. In his opinion they 
were a most excellent bodv of men. It was tlic i)r<)vin( ial local authorities that put the 
extinguisher on a scheme bee ause it was outside the by-laws. Those were the people they should 
defy. He agreed that brick j»anels were better than concrete panels for walls, for reasons of 
economy and l>ecause concrete slabs cra<ked. As to the cost of steel work, he was not aware 
that the prices un which he basc<i )iis calculations were so wild. He denied that no building 
had eve;- been known f) fall ihrough rust, and instanced Ihe case of ("haring Ooss Railway 
station. In his short experienci- of r liinmcjs, he had replaced two steel chimneys with 
reinforced concrete chimneys, and both harl lasted u or 13 \ears. Alluding to the remarks 
of Mrs. Morris, he- said they had in rcinforcc-d (oiMrclc- a i)art i( iilarly suitable material, its 
inherent cjualitics, and the manner in which it (oiiM Ik- put lordlier, affording large window 
space. The steam trouble had beaten better un n ih m he, and no salisfactor\- s\stem had \et 
been evolved to deal with it. 

202 



4r CtJNM UUCTiaNAl^ 
^ KN(ilNKF.PlN(. — J 



RHINFORCFD CONCRETE ROOF CONSTRUCTION. 



NEW WORKS IN CONCRETE 

AT HOME AND ABROAD. 

Undtr this heading relUble information rulll be presented of neiv 'works in course of 
construction or completed, and the examples selected tuill be from Ml parts of the -world. 
It is not the intention to describe these -works in detail, but rather to indicate their existence 
and illustrate their primary features, at the most explaining the idea -which served as a basin 
for the design.— ED. 



REINFORCED CONCRETE ROOF CONSTRUCTION AT LIVERPOOL 

CATHEDRAL. 

ALTHOroii reinforced concrete did not enter lar<^ely into the construction of this buiidinj^, 
some interesting^ work is to be noted in connection with the roof construction. This 
worlv comprises the chapter house and choir roofs and some flat roofs over the small 

towers. . 1 r r 

These latter are octagonal on plan and are finished by stone turrets m the form ot 

pyramids, which are carried by the reinforced roofin<,^ The clear width of the towers is 




risic 



CT-forv o/v /./f^c C 



Section Reinforced Concrete Chapter House Roof. 
Liverpool Cathedral. 



about II ft. 3 in., and each is spanned by four beams, running in pairs at right angles, 
and interlacing one another about 15 in. from the wall face. Small beams having 
similar dimensions are carried diagonallv across the corners of the square thus formed. 
These beams carrv the stone turrets, and the enclosed octagon is left open. 



203 



NEW WORKS IN CONCRETE. 



ICQNCBE TEJ 




b: < 



p: J 



The roof over the choir has 
a clear span of 50 ft. 4 in., with 
a somewhat shallow pitch, the 
inclination from the horizontal 
being 26 deg. The total length is 
136 ft. 6 in., and the whole forms 
an external roof above the choir 
vaulting. The system of construc- 
tion adopted is similar, on a larger 
scale, to that usually employed in 
ordinarv timber roofs. The roof 
space is divided longitudinally into 
three compartments by transverse 
walls 2 ft. 3 in. thick, each com- 
partment having a clear length 
of about 38 ft. At the east end 
there is a smaller compartment 
14 ft. 7I in. in the clear. The 
transverse walls take the place of 
principals, and the intermediate 
spans are bridged by ridge and 
purlin beams. These carry the 
smaller rafter beams, which have a 
span of about 14 ft., are spaced 
8 ft. apart, and in turn support the 
general roof slab. The whole 
forms in reality an ordinary beam 
floor construction, arranged in two 
inclined ])lanes. The ridge and 
purlin beams were designed as 
continuous over three spans, their 
depth being 3 ft. 3 in. at the 
suj)ports and 2 ft. 3 in. at the 
centre of {he spans. The small 
bay at the east end is constructed 
with a single system of purlin 
beams spaced 7 ft. apart. The 
ends of all the main reinforcing 
bars are hooked over to ensure a 
good anchorage, and the web 
tension bars are carried completelv 
around the main reinforcements 
■.[n(] turned down into the centre 
of the beam at th(> top. Where no 
top metal is required for com- 
|)ressi()nal strength, constructional 
bars h in. in diauK'ter are provided. 
The centring to the imderside was 
wrought, and the surface will be 
left without any further finish. 
The exiernal suiface has been pre- 
|)ared to receive copper sheeting, 
hardwood slips being built into the 
slopes to |)r()\'i(l<' fixing. 

'i'he most interesting roof is 
thai wliicli covers the circular 
eliapler housi'. This building 
li.is a ch'ar dianieler of 31 ft. 
al llie roof springing, and the 
walls are i ft. 9 in. thick. 



204 



(&^SMiiS!3 Rh:iNFORCED CONCRETE ROOF CONSTRUCTION. 

An inlcnial nIoiic i^.illcry ciuiirlcs it jiisl below the rool, siipijorlcd by ;ir(hcs 
s|)i iiii^iiii; lioni ilic walls hciicilli. Althoii^^h of ;ini|)le strcnj^th to withstand the llirust 
thus |)Ul upon ihcni, it was considered best that the walls should be relieved of all 
])ossible iliance of additional thiusl from llu- roof above. The internal doni(,' has a 




radius of i6 ft. and rises ii ft. above the sprin^ini^, being 30 ft. 6 in. in diameter at that 
level. The height externally from the springing to the apex of the cone is 22 ft. 6 in. 
To provide against the possibility of thrust, the roof is encircled at the base with four 
series of s-in. diameter bars, each in five lengths, for convenience in handling, with 



20. 



NEW WORKS IN CONCRETE. 



(CDNCBKrilJ 



lapped joints of sufficien. ,cn,th .o develop '•-';',;' ';;-f^4'^;^;; "^ theiT ^ho.: 
securitv the ends are hooked and he U,p. ^f "''■^.^^^'^d '"fitht to assist the walls 



(> 




Longitudinal Section. 







Vs 




View of lUiildinU during Consirudiun. 
Dbsamparados Station. Lima, \'\:kv. 

p,ovid,.d wi,h h. -in.n .n. !,.„■ .lips for Una,.-,- se.uriu. This ,„of will he Hnished wilh 

coppf-r. . , ,, , , in(l(l)i((l lo Mr. (i. (iilbort Scott, the 

a Jt^roT^h: buiiL;:r::; :.u:';;a;:i:.:,,::,. ..,..1 ,1,.. d,.,..w;„.s whi,. 1,,. umdiv piac a. 

our disposal. 
206 



/o, cx5Nyrunc-rioNAii 

' C i FNGITMLE-klNt'. ' 



R}^:iNr()RCIiD CONCRETE RAILWAY STATION, 



REINFORCED CONCRETE AT THE NEW DESAMPARADOS STATION. 

LIMA. PERU. 

Till.- huiUlin- here d.^n ih.d a.v.rs .•.i.i.r<.xim.il.l\ :m .nr.-i of 2,150 ^M- ni., .-.nd consists 
of thr sl.-.tion prop* r, on lb.' -round lloor, .md ihr oHics .,1 ihr i.nlway st;dl, on Hi.- Iwo 
upper tloors. 




•TT??'^' '"ft-^- 



The structure is mainlv of reinforced concrete. There are 92 reinforced concrete 
columns running through the three stories. The floors and roofs also are composed of 
reinforced concrete girders and slabs. All partitions are of hollow bricks, whilst the 
front of the building is faced with pressed blocks of cement and sand to imitate sand 

stone. 

207 



NEW WORKS IN CONCRETE. 



ICQNCBETEJ 



1 


■■■ 


1 










^Bi 


1 


1 






^^^^= b 






HI 592 


!!! 


Niiia 


^^JH^^^^^H 


1 


"I 


, 



Concrete Block Crusher Station, Prestea, West Africa. 




CONCRKIK I'l.'K K l.OAOINfi STATION, I^(KSTICA, WkST AlKICA. 






CONCRETE BLOCKS IN WEST AFRICA. 



A j^Dod idea of llir Ijuildiiij^ will l)c obl.iiiKd fioin Ihc .•ircoiiip.iiiNiii}^ illustrations. 

The whole ol ihc work w.is c;ii lit d out in U) nioulhs. The arcliitcct w;js Mr. R;if;i(l 

I". M ;irt|uin.i, whiUl the it inlnr(';<l i"on(i(lc work w.is dcsit*nc(l ])\ Mr. M . M. I'.ilo. 

W'c .lie iiulchtcii to oJic ol oui' i()rrcs|)()iid( Jil >^, Mi. O. L. Ali.ii^.i, lor our |)]lolo^r.'^|)ll>^ 

■ iiul paiticuku's. 

CONCRETE BLOCKS IN WEST AFRICA. 

\\ ini( I csl iui; ;i|)|)lic.".it ion of the use of concrete blocks foi- mine w oi'l< will be seen bom 
ibe illustrations on paj^i' 2()<S, >bowini4 some work carried out on the (lold Coast. 'IIk 
ilkrslralions sliow a new Loadini; Station and a new Crusher .Station at tlio Prestea 
Ciold Mines (Rlock .\). " Winj^et " blocks were used llirouj^hout for tliis work. 

The c'ontractors for the woik were .Messrs. I hompson, Moir \- (ialloway, of 

J'arquah and Prestea, (iold CoasI, West Africa. 




NEW BOOKS. 



NEW BOOKS 

AT HOME AND ABROAD. 

A short summary of some of the leading books ivhtch have appeared during the last feiv months. 



"Reinforced Concrete Construction." Vol. II. 
By George A. Hool, S.B. 

The Hill Publishing Co., Ltd.. 6 and 8 Bouverie 
St., Fleet St.. London, E.C. 666 pp. + viii 

Contents. — Retaining Walls — Theory of 
Stability — Design — Construction — 
Buildings— Design — Floors — 1 ypes of 
Reinforcement — Roofs — Columns — 
Foundations — Walls and Partitions — 
Stairs — Elevator .Shafts —Contraction 
and Expansion — v-ontinuous Beams — 
Eccentric - load Considerations in 
Columns--Wind .Stresses — Design of 
a Factory Building — Example of a 
Building Design, including the Speci- 
fications — Construction — Materials 
—Forms — Bending and Placing of 
Reinforcement — Proportioning, Mix- 
ing, and Placing of Concrete — Finish- 
ing Concrete Surfaces- — Waterproof- 
ing of Concrete — Construction Plant 
— Estimating Unit Costs- — Estimating 
Quantities — Example of an Estimate 
for a Concrete Building. 

This is the second volume on reinforced 
concrete by this author, and the first 
volume, which was reviewed in these 
columns in a previous issue, treats of the 
fundamental principles, and has been 
adopted as a text-book in a number of 
technical schools in America. 'I'he pre- 
sent book deals with the more advanced 
portions of the subject, and should be of 
service to engineers in practice, as well as 
to the advanced student. The diagrams 
throughout the book are excellent, and 
these have been prepared for the author by 
Mr, Frank C. Thiessen, with the ic'xcei)- 
tion of those pertaining to Construction 
Plant, the chapter on the latter having 
been f)repared by Mr. A. W, Ransome. 
The chapters on Estimating have been 
written by .Mr, Leslie H. Allen, and these 
form a us(;ful [portion of the book. 

The theoretical f;arts of the subject ;ire 
treated in a very thorough manner, and 
the author does not appear to rr)nsider any 
f)oint too small or unimj)ortant to be iin 
worthy of explanation, 'ihis section is 
well arranged, and (he various examj)les, 
which are com[)letely worked out, are 
given in such a manner that the reader is 
able to follow the a[)j)lication of the tlxoiN 



and set his mind at rest on any point which 
does not appear quite clear at first sight. 
The practical portions are illustrated with 
numerous photographs of work actuallv 
executed or in course of construction, and 
these render this section of the volume 
ver\' interesting. 

The shear and moment considerations 
in continuous beams are dealt with very 
fully, and great pains are taken to instil 
the elementary principles into the mind of 
the reader before proceeding to the more 
complicated reasoning and formulae. The 
English reader may experience a little 
difficulty owing to the fact that the nota- 
tion is different to that generally employed 
in this country, but a study of the book 
will well repay the reader. 

" A Manual for Masons and Bricklayers." 
By J. A. Van der Kloes. Revised and 
adapted by Alfred B. Searle. 

London : J. & A. Churchill, 7 Great Marlborough Street 
W. 235 pp.-»-xii. Price 8/6 net. 

Contents. — Physical and Chemical Notes 
—Masonry — Bricks and Stones — Raw 
Materials used in the Preparation of 
Mortar — The Composition, Prepara- 
tion, and Use of Mortars — The Com- 
position, Preparation, and Use of 
Concrete — Other Work Executed by 
Masons, Plasterers, etc. — Estimates 
and Costs. 

This volume has been prepared by Mr. 
.Searle to put before English and American 
readers the researches of Professor Van 
der Kloes, who is the Professor in the 
.Science of Materials of Construction in the 
L^niversity at Delft, and the particulars 
have been modified and adapted to render 
them more suitable to the readers in this 
country. Great stress is laid on the neces- 
sity of using suitable mortar in all kinds 
of construct ion.il brick and stone work, 
and the pliNsical and chemical notes which 
(leal with ihc defects that commonly occur 
are interesting and certainly put the 
various items in a new manner which is 
(•]< ar and convincing. 

Shrinkage and e.\|)ansion, watertight- 
ness, weathering, wall canccM", and 
osmosis are among the points dealt with, 
:iU(\ the whole chapter forms a good 
iiilrodiiction to the book. 



2 lO 



. lONMPIR-IIONAlJ 
fvLNdlNl i I'INd — J 



NEW BOOKS. 



Ch'ikimIIv s|)(;ikiiu^, ihc ])r;utir,il notes 
art' 111)1 St) j^t)t)cl as tht>S(' clfvt)lttl it) ilii 
ihcDii^tiral aspt'ii, and it is from the lain r 
that tht' most valuahli- inft)rmation t an \)r 
t)btaincd. 

Tilt' nolfs t)n it'inftirt'td coiu'itic aif 
\r\\ iiitai^it', and lurtlu rmt)rt' do nt)t 
fxprt'ss the nature and functit)ns t)f ilic 
oom|)t)ntMit i)arts in a satisfactory niannci , 
altlu)uj4li till' author states that thf usf of 
the material ensures a security ai^ainsl lire 
which is imobtainable in any other \\a\". 
There are many points in this section of 
the work which will not be accepted by the 
majority t)f enifineers, but they are of some 
value to the reader nevertheless. Various 
suiijjjestions are gi\'(>n for the surface treat- 
ment of concrete, but the author is not of 
the opinion that a rich architectural treat- 
ment can be obtained without the use of 
brick or stone facing. 

" LocRwood's Builders' and Contractors, 
Price Booh for 1914.' 

This price book is for the use of 
architects and surveyors and those con- 
nected with the building trade. It has 
been brought carefull)' uj) to date, and due 
effect has been given to the rise in prices 
of materials and labour in the various 
trades. 

The first part of the book deals with 
every kind of building work, and the prices 
and wages tables have been brought up to 
date and considerably enlarged. The 
section dealing with electric lighting has 
also been added to. 

Much useful information is given in the 
appendices, in which are tables of weights, 
areas, etc., solicitors' costs, stamp duties, 
tables for the valuation of leases and 
estates, legal notes and memoranda, as 
well as judicial decisions and Parliamen- 
tary enactments. 

There is also the form of Building 
Contract and Schedule of Conditions 
issued by the Royal Institute of British 
Architects, as well as a copy of the London 
Building Act and its amendments. 

* Spon's Architects' and Builders' PocKet 
Price BooK." 

This well-known price book forms a 
valuable reference for all those in anv wav 
connected with the building trade. 

The book has been brought thoroughly 
up to date, and a great many additions 
have been made in the various prices, so 
that the diarv has had to be omitted to 



kftp llif l)t)ok a reaNonable sizt- Itir pocket 

UM'. 

The usual t)rd(r of tratles is adojjtt d as 
in a well-drawti bill t)f t|uantities, antl 
I Ik re is a fulls-'lelailed indf.x to the trades, 
so ill ii any in'^oriMalion which is required 
is (.juiekh ft)und. 

''The Maintenanceof Foreshores." By Ernest 
Latham. A.M.Inst.C.E , A.M Inst.M.E. 

I.iin<iiiii : Cr( shy, I .nckwood vV Smi. 11*1? h4 pp. 
Price 21 - nti. 

This little book deals with a subject of 
great interest and importance, but in a 
\'erv incomj)lete manner, being hardly 
more than a grouping of detached notes on 
certain aspects of the subject. .Some of 
these nt)tes are, however, highly sugges- 
ti\-e. The Royal Ct)mmission on C'oast 
I%rt)sit)n has presented an extensive report 
(a sht)rt summary of which is given in this 
book), indicating the urgent necessity of 
protective works. Legal problems of a 
somewhat intricate character present them- 
selves in this connection, and the author 
deals with these and with the closely 
related question of administrative authori- 
ties. On turning to the practical means of 
protection, however, the reader is disap- 
j)ointed, the treatment of this subject being 
rather scrappy and of less value than 
might be expected from an author of such 
experience in the execution of coast pro- 
tection works. 

It may be noted that groyning, as com- 
monly carried out, is considered to do 
almost as much harm as good. Favour- 
able reference is made to the Dutch svstem 
of protective aprons, and the suggestion is 
thrown out that such aprons might be im- 
l)roved by oblique steppings, at right angles 
to the prevailing set of the waves. No 
details of the method of construction of 
protective works are given, and there are 
no illustrations. Some notes on the pre- 
paration of concrete are included, but the 
account of reinforced concrete only 
extends to a page, most of which is occu- 
pied by tests of the steel reinforcement. 
Exception may be taken to the statement, 
referring to reinforced concrete sea walls, 
that the system to be adopted is the first 
consideration. The principles of construc- 
tion of aprons, etc., are now sufficiently 
well understood for the competent engineer 
to design his reinforcement without slavish 
adherence to any patent system. 

Colonel Crompton contributes a chapter 
on surfaces with bituminous binding for 
marine promenades. 



21 I 



NEW BOOKS. 



ICDNCBETE 



" Experimenis with Built-in Beams." (Ver- 
suche mit Eingespannten BalKen.) By 
Dr. Fritz E. von Emperger. 

Lepzig & Vienna: Franz Deuticke, 1913. 259 pp., 
250 Illustrations and Plates. Price M. 10. 

This memoir contains a full descrii)li()n 
of the experiments, an account of which 
has already been given in this journal. It 
mav be regarded as forming a complete 
treatise on the theory and practice of the 
subject, and is very fully illustrated by 
diagrams and photographs. The principal 
conclusions drawn from the very extensive 
experiments on a large scale may be re- 
capitulated here. 

All reinforced beams which have been 
erected without special devices to ensure a 
free bearing must be regarded as wholly 
or partially fixed, and allowance must be 
made for the fixing moments. It follows 
that the compression zone in beams should 
never be entirely without reinforcement. 
With sufficiently good union of beam and 
bearing, the beam may be computed as 
completely fixed, in which case the abut- 
ment mav be considered to include an 
element of the wall broader than the beam, 
to an extent depending on the quality of 
the masonry or concrete. It is best to 
make the reinforcement of beam and wall 
continuous, as in framed construction, but 
precautions must be taken against settling. 

The book is handsomely produced. 

" Technical Studies of Mortar and Cement " 
iZement-und MJ5rteltechnische Studien 
I.) By Dr. Hans Kvihl. 

Berlin : \'fcrlaf< der Tonindustrie-Zeitung, 1913. Price 
5 Marks. 

Ur. Kijhl is the successor of the late Dr. 
W. Michaelis, and his investigations into 
the chemistry and technology of cement 
have the same originality and interest as 
those c)f his distinguished j)redecessor. 
This little collection of memoirs and ad- 
dresses deals with a variety of subjects, 
from the expansion of cement containing 
sulphates to the use of gas analysis as a 
means of controlling the fuel consum})tion 
in rotary kilns. Concerning the first point, 
the author produces evidence to show that 
it is not the absolute quantity of sulphates 
which determines expansion, 1)ut its ratio 
to the lime ccmtent. Thus with cements 
of hvdraulic mfjdulus 2*30 to 2' 15 the best 
result is obtained with 3 per cent, of 
gvpsum, whilst n cement low in lime, with 
h\(lr;iiilic inrxlulu'' i''*^5, i^ sli'ongesl with 



b per cent, of gypsum, and in fact the true 
Portland character does not appear in such 
cements until the proportion of gypsum is 
considerable. 

A new test for constancy of volume was 
proposed by the author in 1912, consisting 
in boiling tests with thin pats of the 
German form, but made with mixtures of 
cement with very finely ground normal 
sand. It is to be noted, however, that 
manv cements would pass this test which 
fail in the Le Chatelier test. The use of 
fluates is recommended for the treatment 
of cement and concrete surfaces which are 
to be ])ainted with oil paint. 

" Silo Construction in Concrete and Rein=> 
forced Concrete." (Silobauten in Beton 
und Eisenbeton.) 

(Heft 4 of Cement - Verarbeitung.) Cement -Verlag 
G.m.b.H., Charlottenburg, 1913. Price Pf. 35. 

A pamphlet detailing the advantages of 
concrete, especially reinforced, for the con- 
struction of silos. Descriptions, with many 
plans and photographs, are given of silos 
which have been erected to contain grain, 
coal, ores, cement, wood-shavings, etc. 
The methods of reinforcement and of 
statical computation are also described. 
Rectangular, cylindrical and hexagonal 
silos have been used, and the types of 
design and construction may be varied 
widelv according to circumstances. It is 
evident that reinforced concrete is in every 
way superior to steel, wood or brickwork 
for structures of this kind, the number of 
which is increasing rapidly. 

" Posts and Masts." (Pfosten und Maste.) 

(Heft 3 of Cement -Verarbeitung.) Cement -Vtrlag 
G.m.b.H., Charlottenburg, 1913. Price Pf. 30. 

Another of these useful little German 
monographs, describing the design and 
construction of reinforced concrete posts, 
telegraj)h poles, tramway .and electric light 
standards, etc. The lightness of construc- 
tion which is j)ossible with this material is 
surprising, and some excellent examples of 
really graceful and artistic standards for 
lamps, tramways, etc., are reproduced. 
The high elasticity is shown by bending 
tests, liie masts returning comj)letely to 
their original form after a deflection 
.'imounting sometimes to as much as a 
metre ;il the free end. On account of the 
(lillicnlly of construction, these long masts 
;iic iisii.ilJN' made by special firms using 
[).il<nle(l processes. 



2 I 2 



7/, tON> IPnCTlONAI. 



MEMORANDA 




Memoranda and Neivs Items are presented under this heading, with occasional editorial 
comment. Authentic neivs will be ivelcome. — ED. 



Building By-Laws and Reinforced Concrete.— The C'hiswick Urban District 
Council, under their Act of 191 1, obtained powers to relax or modify their by-laws 
with respect to new streets and buildinfjs as to buildinj^s of iron, steel, or reinforced 
concrete, and have recently made ihe following regulations : — 

(i) All future one-storey ferro-concrete structures be considered permanent build- 
ings, provided that in the Co-unciTs opinion sufficient strength is allowed for in the 
construction of (a) supjxvrting walls, and (h) all flat pitched or horizontal roofs. 

(2) That fcrriKconcrcie dwelling houses be considerod jxTmanent buildings, jjrovided 
that all floors are calculated to carry a minimum load, including the weight of the 
floor, of one-and-a-half hundredweight per foot super, with proportionate strengths 
for supporting walls. 

(3) That ferro-concrete factories, warehouses, and public buildings of more than 
one storey be not approved as permanent buildings, unless an undertaking by the 
owner is deposited with the plans, etc., stating that he will not permit or allow the 
agreed maximum safe loads as set forth upon all parts of such plans to be increased 
in any part thereof without the permission of the council being first obtained, 

(4) That the recognised general engineering formulae for beams supported at each 
end be utilised for all calculations except in the case of continuous beams over three 
or more spans, in which case the external spans must be treated as beams supported 
only. 

(5) That fully detailed plans, sections, and elevations of all reinforced concrete 
buildings must be submitted with a detailed specification, and on such drawings must 
be shown the proposed maximum loads, together with the calculations upon which the 
strength of all walls, columns, floors, and roofs have been calculated. 

Action of Sea Water on Concrete. — More than twenty concrete piers built several 
years ago by the Aberthaw Construction Co., and submerged in the United States Navy 
Yard at Boston, are again being examined to note the action, both mechanical, due to 
frost, and chemical, due to ingredients in the sea water. As this subject is one which 
has a large bearing on the permanence of piers, abutments, sea walls, etc., when built 
of concrete, these experimental tests are expected to yield some very valuable results. 

Wire Ropeway Supports in Concrete and Reinforced Concrete. — Wire ropeway 
supports were originally only made of wood or iron. The wooden supports were bedded 
into the earth, or they were mounted in the same way as iron supports on masonry 
or concrete. The necessity arose occasionallv of throwing hot ashes and slag from the 
carrying rope of supports on to a dump, and the supports were gradually buried in. 
Danger thus arose of large parts of the dump catching fire, and for this reason neither 
wooden nor iron supports were suitable. Means were resorted to to remove the pressure 
of the dump material from the supports. These were then built of bricks, or stamped 
concrete pillars were set up as raised foundations on which only short iron carrying 
heads were fixed. Supports of this kind were made by Messrs. Adolf Bleichert, of 
Leipzig, and our second illustration shows such supports erected some 3-ears ago for 
the sugar factory of Messrs. Dobrovitz, in Bohemia, by Messrs. Bleichert. Latterly 



,** 



213 



.^'t.g, 






^lil^in 



CONCKLTEX 



rCONSTRUCTIONAJL^ 



J^.,..^ 




PILE DRIVING PLANT 




WE MAKE PILE DRIVING PLANTS SUITABLE FOR THE 
LIGHTEST TIMBER SHEETING OR THE HEAVIEST FERRO- 
CONCRETE PILE, FOR STEAM, AIR, OR HAND POWER 



STEEL SHEET PILING 



*' Universal Joist 

''Simplex" 

"Simplex" 



43 lbs. per super, ft. 
27 lbs. 
22 lbs. 



»5 J» 



Wc buy tlie Pilin^^ back at \\\f- v.n\ of the job, making llie cost to ihe user approxlmalely 
1/10, 1/4, & 1/- per 8uj)er, foot rcs[)ectively 



CATALOC.UIS AND FIRM Qll ITATIONS ON APPLICATION 

THE BRITISH STEEL PILING CO. 

DOCK HOUSE, BILLITER ST., LONDON, E.C. 

Telephone : 5463 Av<;nu'-. 



I ilcHrains ; " I Minifdon," I ondon. 



2 14 



Please mention this Journal ivhen luritinq. 



E 



J lONMkMlcriONAl 
f-i. KNdlNl-l KMN(. --. 



MEMORANDA 



aclu.il ri'iiiforccd concrete supports have 
been creeled for ceiiKMit factories which 
carry the rojxs on cross-beams. These 
are seen in the lirst illustration, and 
were built for a cement works abroad, 
.111(1 were made by the same firm 
iiK iilioned above. 

Sieving witti Standard Cement 
Sieves.' 'ihc Bureau of .Standards, 
I .S.A., have recently issued a Paper 
(No. 2()), by Messrs. R. J. Wig and 
J. (-. Pearson, dcalinj^ with variations 
in results of sicvin<4 with standard 
cement sieves. We are unable to ^ive 
I he report in full, which deals with 
\ arious experiments carried out, but we 
publish below the conclusions arrived 
at, as they may be of interest and prove 
useful to many of our readers : — 

In reviewinif the results of the 
tests made the following conserva- 
tive estimates may be given : 

I. Emj)lo\ing the present stan- 
dard method of sieving, the greatest 
attainable accuracy in single fine- 
ness determinations of normal 
Portland cement on a standard 
No. 200 sieve — that is, the greatest 
attainable accuracv in checking uniformity of samples— is about o-2 per cent. 
2. " Standard'"' No. 200 sieves may differ in their sieving values by consider- 
able amounts, such that their corrections to the ideal No. 200 sieve may be at 
least as great as 0*7 per cent. 




Wire Ropeway Supi'orts in Reinforced Concrete. 




Concrete Wire Ropeway Supports. 



21 



MEMORANDA, ECT>[CBETE} 

3. Errors of at least o-^ pcv cent, may be looked for in sinigle fineness 
determinations of normal cements on a standard No. 200 sieve when made in the 
usual routine manner. 

4. Deviations exist in the sieving values of " standard " No. 100 sieves, of a 
magnitude, roughly, one-half the corresponding values for No. 200 sieves as given 
above. 

5. " Personal equation " appears to be appreciable in hand sieving, as in most 
laboratory operations, the observed values being as great as 0-3 per cent. 

6. The rating of a sieve by some system of demerits assigned from direct 
measurements appears to be an interesting possibility, and worthy of further study. 
Should a system be worked out to give reliable indications, say within 0*2 per 
cent, or 0*3 per cent, of the observed sieving value of a sieve, it will add greatly 
to the value of the certificate now furnished with standard sieves. 

It seems e\ident from the foregoing that both sieving tests and the iuiterprota- 
tion of measurements on sieves are subject to conisiderable discrepancies, and the 
question arises as to whether some other more reliable method of determining 
fineness cannot be made available. The sieve at best is a measure of the coarse- 
ness of finely ground material rather than the fineness, and experiments now in 
progress at the Bureau of Standards indicate that air separation will offer a more 
satisfactory means of determining fineness than mechanical sieving. 

In conclusion it may be stated that a tolerance of i per cent, from the specifica- 
tion should be allowed with the No. 200 sieve and 0*5 per cent, from the 
specification with the No. 100 sieve, every care being taken to conduct the test in 
strict accordance with standard methods. These tolerances should be considered 
as minimum values since they are based upon the results obtained by careful and 
experienced observers ; therefore it should be emphasised that greater differences 
are possible in ordinary routine testing. 

Concrete" Hardening Material. — A material for hardening concrete now being 
introduced in the United States contains 95 per cent, of iron dust, which is mixed with 
cement for finishing the surface of concrete floors. From 15 lb. to 25 lb. of the material 
is mixed with 100 lb. of the cement while dry, and one part of this mixture to two 
parts of sand mak<'s the slurr}' for the top coat, which varies from 0*5 to i in. in thick- 
ness. It is said to make a hard and durable floor, which is waterproof and not 
slippery. The hardening material is used also to make new concrete adhere to old 
in repair work. 

TRADE NOTICES, CATALOGUES. ETC. 

The Kahn System of Reinforced Concrete. — Most of our readers are well 
acquainted with this form of reinforced concrete construction, and we have in this 
Journal given illustrated articles and descriptions of buildings and other work erected 
on this system. 

A new catalogue has just been issued bv lire 'i'mssed Concrete Steel Co., and 
every endea\'our has been used to produce this juiblication in an attractive manner. 
The book is jirinted on the loose-leaf system, so as to enable sections of it to be sent 
out to people interested in the respective subjects illustrated. 

It contains numerous illustrations of important structures carri<(l out on this 
system. 

There are also some notes dealing with the siibjccl of reinforced concrete generall\% 
and a few pages are also d<'Voted to describing the Kahn sxstem in j)articular. 

Those of our readers desiring U)Y fiirllu t iiifonnnlion, or a copy of the catalogue,, 
should a[>[jl\' to llir- Trii"«se(l CoiKrcle Steel ("o., of ("axton House, Westminster, S.W. 
The Empire Stone Co., Ltd. A new catalogue has just reached us from this 
company. This publication contains a luinilxr of iiilcresting examples of buildings 
in which reinforced r-oncrele has been ein|)loycd. Not onK are the various woilvs 
illustrated, but in each case a short disc ri|)lion is given of ilic reinforced concrete work 
carried out by the comjjanw 

The examples includr- factorx' const rmt Ion, rclaliiing walls, staircases, bridges^ 
rafts, etc. Copies of the catalogue may be oblaiiicd on a|)plication to the company at 
Thanet House, 231, Siranfl, W'.C., or al tlicii- ofticis in Birmingham: ^\'inchesler 
House, Victoria Square, Hirminghani. 

2 16 



CONCRETE 

AND 

CONSTRUCTIONAL ENGlNEEmNG 



X'olume IX. No. 4. London, Ai'KII., 1914. 

EDITORIAL NOTES. 



THE CONCRETE INSTITUTE. 
The Present Unfortunate Effort to Change Its Objects and Title. 

We ha\c from limL' to lime referred to a tendency on the part of certain nu-ni- 
bers of \\\<i Concrete Institute towards utilising the Institute for their ])articular 
purpjses. The. e members have been very persistent in their tndtavours. It has 
thus come about that althoug-h the general membership had not realised it at the 
time — and. as a matter of fact, many members of the Institute's Council had not 
realised it either — a change of Memorandum was adopted at an Extraordinary 
(General Meeting last winter whereby the Institute, instead of remaining an 
institute intended for those concerned in works in which concrete and rein- 
forced concrete play a part, is apparently to become an institution for those 
concerned in structural engineering. 

Now we grant that there may be ample rot^m for some institution con- 
cerned specificail}" in structural engineering, although our own experience is 
that the Institution of Ci\ il Engineers and the several junior engineering 
societies have long afforded ample facilities in this direction, and we would 
naturally not raise any objection to such an institution being formed if there 
were a bona fide dc^mand for its constitution. But for those concerned in struc- 
tural engineering to change the entire objects of the Concrete Institute and 
subordinate concrete and reinforced concrete to structural engineering would be 
a mistake indeed. One has only to remember how unkindly reinforced 
concrete was for many years treated in the Institution of Ci\il Engineers to 
understand what its position would be in the Concrete In.siilute if the objects 
and title of that bod) were changed. 

The Concrete Institute was primarily intended for the exchange of experience 
between all the various professions and industries concerned in concrete and 
reinforced concrete, which included CWi\ Engineers, Architects, Sur\eyors and 
Quantity Survexors, Mathematicians, Scientists and Industrial and Cement 
Chemists, Manufacturers and Contractors, and last, but not least, the Concrete 
Specialist. The Concrete Institute, as it is now apparently the intention to 
re-model it, is. however, simply to become an institution of structural engineers, 
and thus the architect, the chemist, the scientist, and the mathematician is either 
ruled out altogether or is to play a very secondary role as an '' Associate," or 
what not. 

2 17 



THE CONCRETE INSTITUTE. CQNCBETE] 

Application to the Courts. 

Leg'ishition, liowcxcr, lias fortunately provided that chang-e in the 
Memorandum of an incorporated institution of this kind must have the sanction 
of the High Court, so that errors may be avoided and the interests of the 
members as a whole safeguarded. 

From numerous letters we have received, it would appear that the Court is 
to be applied to in the near future, but several sections of the professional 
members, a group of those concerned in the co'ucrete industry, and one or two 
other groups, appear to be org-anising opposition. On the other hand, some 
of the municipal surveyors appear to welcome the change, and the steel frame 
contractors and their assistants are jubilantly delighted. 

Our View. 

Our own view on the proposed change is obvious. We have assisted the 
Concrete Institute with advice and publicity as a corporation with a specific 
purpose. We consider an independent Concrete Institute a necessity and 
approve its original objects and constitution. It is our intention to use every 
possible legitimate endeavour that those objects be retained. We shall thus 
oppose to the best of our power any change that diverts the objects of the 
Concrete Institute from its primary purpose, and we shall certainly oppose any 
change from its very excellent and concise title. 

Apart from the question of the Concrete Institute per se, we think it is 
a national question that this country should have a bona fide Concrete Institute 
and not lag behind other countries in this direction. The Empire requires some 
centre where all professions and vocations concerned can exchange opinions on 
the subject, and also some centre that can speak independently as representative 
of all the interests concerned in these important days of new developments in 
building — both domestic and utilitarian, 

A Referendum of our Readers. 

l-'or this reason, we propose also sounding the general view of our many 
subscribers and readers as far as it is possible on the subject, and we are 
enclosing a postcard which we wall thank the recipients to return (stamped or 
unstamped), but filled in in such a form as to give us some idea as to the general 
\ieus of our supporters on this subject. It is equally importaiit for us to know 
tlie views of (jur most junior readers in a far distant colony, as it is to know 
that of the great engineer who practises in (it. George Street. It is equally 
imprjrtant for us to know the views of individuals and of corporations, and we 
trust that the postcard will be replied to b\- a large number of our readers. In 
these da\s of "referenda" and polls, it is particularly useful for us to know 
what the feeling on llie subject is, seeing that v.vvn the great majority of the 
members of the Cxjncrete Institute ha\'e not had an o])j)ortunity of voicing their 
views on the- subject, the attendance at meetings being naturally limited to a few 
London members. 

W^e will u<;lc<jme, apart from tiic icply to lh<; |)ostcard, corresj)ondence on 
the subject. Our endeavour is to retain lor tlu- nation a Concrete Institute of 
standing that may have the sam<; prestige in respect to contTete in the world as 
the prestige of the Iron and Steel Institute for steel, or tlie Institution of Naval 
Architects in the matter of ship (()nstru( tion. The reputation must not only be 

2lS 






THE CONCRETE INSTITUTE. 



A national ri'i)ulat ion, hiil an inlii n ilional rc|)ut al ion, and tliis tinkering at the 
Memorandum and ArtiiK-s of tlu- C'oiuirlc Inslitulc is latal to tlic standing- ol 

lliis l)od\ . 

A Possible New Organisation. 

W'c think it is oni\ lair to aimouiuc that we ha\c Ixcn approached irom 
;;n cnlirrly uncxiici^ti-d and wvy pouciliil source to lorin another institution 
solel\ in the interests of concrete and reinforced concrete, shoukl the objects (jf 
till' institute or its title reallx he chanj^ed with th.e sanction of the Court. We 
think that consideration of this matter is premature, as we have some doubt as 
to the Court sanctioning a change of Memorandum opposed by influential 
members and, may be, by other corporations and by the public. We have thus 
for the j)resent declined even to consider the matter. 

Hut the fact that some such idea has been mooted by distinguished men 
solely interested in scientific and experimental aspects of the subject and who 
are not connected with the Institute should make that body reconsider the 
advisability of the chang-e of objects and title so ardently desired by some of its 
strenuous members, and also whether it is worth while to fritter time and funds 
on interminable strife — within and without — which waste of effort and money 
can result in nothing less than the institution's g^radual collapse or supc^rsession. 

REINFORCED CONCRETE AND INTERNATIONAL INVESTIGATION. 

Whilst at home some people seem to think that investigation relating to 
concrete and reinforced concrete is not a sufficiently wide field for a Concrete 
Institute, international and foreign bodies continue to set up new organisations 
to cope with difi'erent sections of inquiry, for which there is not only a demand 
among the professions concerned, but considerable popular interest. 

Besides the well-known International Commission on Reinforced Concrete, 
formed at the instance of the International Testing Association, to which we 
have had occasion to refer from time to time, the Association in question 
has also taken the initiative in forming two further International Commissions 
that should have an important bearing on reinforced concrete. 

Fire Resistance of Reinforced Concrete. 

The first of these is an International Commission on the Fire Resistance of 
Concrete and Reinforced Concrete. Delegates have been nominated from all 
the principal countries in Europe and from the United States of America, and 
Mr. Edwin O. Sachs, F. R.S.Ed., Chairman of the British Fire Prevention 
Committee, has been elected President of the Commission. The British 
delegates, we should here add, are Mr. Ellis Marsland (district surveyor) ; Mr. 
W. Kirkcaldy, A.iNI.Inst.C.E., head of the well-known testing laboratory; and 
Mr. D. W. Wood, an insurance surveyor. 

The American deleg'ates are the following : — Professor Ira H, Woolson, 
National Board of Fire Underwriters, U.S.A. ; Mr. Richard L. Humphrey, Pre- 
sident American Concrete Institute; Professor Charles L. Norton, Massa- 
chusetts School of Technology; and Mr. R. P. Miller, vSuperintendent of Build- 
ings, New York. 

\\'hi]st amongst other delegates we would specially like to name the 
following appointments : — From Germany : Professor Gary, of the Lichterfelde 

B Zl9 



INTERNATIONAL INVESTIGATION. ICQNCBETEl 

Testing Station, and Chief Oflicer Westphalen, of the Hamburg Fire Brigade; 
irom Austria : Professor Melan, of the Technical College, Prague, and 
Professor SaHger, of the Technical College, \'ienna ; whilst from Denmark 
the delegates include Chief Officer Liisberg, of the Copenhagen Fire Brigade. 

Reinforced Concrete Accidents. 

The other International Commission that has been formed is an Inter- 
national Commission on Reinforced Concrete Accidents, and of this Dr. von 
Emperger, of \'ienna, has been elected President. The British delegates in this 
case arc: — Mr. Edwin O. Sachs, F. R.S.Ed.; the Concrete Institute is repre- 
sented bv Mr. H. Kempton Dyson (Secretary) and Mr. S. Bylander. Australia 
has in this instance also three delegates, viz., Mr. J. J. Clark, architect (Mel- 
b(jurne); Professor \\\ H. Warren, Sydney University, and Professor Robert 
Scott, Canterbury College (Christchurch, N.Z.). 

The delegates from the United States are : — Mr. Richard L. Humphrey ; 
Professor A. X. Talbot, of Illinois University; and Professor F. E. Turneaure, 
of Wisconsin Uni\'ersity. 

Of other countries the following are distinguished members :— Denmark 
has, among her delegates. Professor E. Suenson, of the Copenhagen 
Technical School ; France, Professor Mesnager, director of the Laboratory of 
Ponts et Chaussees, and Mons. Hennebique ; Germany has Dr. W. Petry, of 
the (ierman Concrete Institute; and Switzerland, Professor Schiile, 

We here would specially point tO' the interesting feature that Japan has in 
this instance also appointed three delegates, viz., the following: — Professor 
Tadahiko, of the Imperial University, Kyoto; Dr. Shinzo Kassai-Onoda, of the 
Onoda Cement Co. ; and Professor Kaisaku Shibata, of the Imperial University 
at T<;kio. 

WorK of International Commissions. 

International Commissions of this description naturally work very slowly, 
and the resolutions they arrive at are rarely unanimous, but their great advan- 
tage is, that they generally get together an enormous amount of valuable 
informal ion, which, if properly summarised, becomes invaluable as comprising 
the reliable- and authentic data of the points at issue. 

In Ixjlh the cases of the International Commissions here referred to the 
quest i(;n 'jf pre st nling useful data is one of importance, and reliability the great 
factor. We (hjubt if the Commissions on Reinfon^'d ConcTete Accidents can 
come to an\- other result b(');)nd a i)rescntati;)n of the primary causes of 
accidents, but in the case of the Commission on the Tire-Resistance of Concrete 
and l\(iii(or(4-rl ('(jiicrc tc it is to Ix; hoped that some standard specification may 
be e\rjl\ed rnurji on ihc lines ol \\\i I'iic Insurance Specification we have 
referrerl 1o« in a pn \ ions is.sue, and which, in a few short words, indicates on 
general lines only what is absohilcl) essential IVom the lire jDoint of view. 

A Warning to the International Testing Association. 

The Internat ion.il 'Icsting Assix i;i! ion ji.is doiK- much good work in form- 
ing these International ( "onimissions, .nid the re|)orts of souk; of the Commis- 
si'^)ns in parlicul.ir lia\c bcin ol iinnicisnr.ihlc \;ihic. Tivere is some danger, 
however, thai llicy sliould touch on subjects thai nia\- be controversial from 

220 



rj.fCN.MK'UiriONAl.l 
/vt.N(.lNl-l l^NC. --J 



SIR HENRY TANNHR. 



\hv iii(liislri;il ;is|)r<t, ;iii(l for this riMsoii 1 nlcnialional spt'cilications on such 
suhjcH-is as I'orllaiul C\nu nl or on the (iii;ilil ics of Slci'l and other niclals 
should 1h' avoided, nioir panic iilarly ;is vii< h suhjecls arc dcpundent ^'•cncrally 
or. local rondilioiis and local innu'ial pioihids. 

Now ihat a Hrilish section has been propnly orLjaniscd to reprcscnl I^ritish 
interests in llu' International Testini;- Assoeialion, it is to he hoped that this 
aspect of ihj Association's work will ha\e i)rop-er attention, for there was a 
tcndencN — pa.rticuiarly on tlu' ])ari of the multitude of (Jerman members wlio 
ratlH'i- strenuously ix-present tlu' interests of their nation on this parti<-ular 
ori^anisation to utilise the Inlernat ional C'onnnissions h)r tint (M)nimercial 
purposes of their (^ounlry. 

We welcome the formation of Research Commissions such as the ones 
referred to abov€, but shall be \ er\' wary of .-mythin^- in the way of Commissions 
that attempt the international specification of our national products t^enerally 
to the disacKantao-e c)f our coimtrv. 

SIR HENRY TANNER. 

W'h observe that the public Press has announctd that Sir Henry Tanner, C.B,, 
has retired from his post as prmcipal architect to H.M. Office of Works, after 
some forty-two years' service with that department. His present post he has 
held since the retirement of the late Sir John Taylor in i8g8. 

Fortunately, however, we are able to announce that His Majesty's Govern- 
ment has very wisely retained the services of Sir Henry Tanner in a consultative 
capacity, so that although he may not be in that hourly attendance at Storey's 
Gate which is almost necessary nowadays for one holding the position of chief 
architect, and althoug-h Sir Henry Tanner will be free from that incessant grind 
of routine work which is becoming more and more a feature of modern methods 
ot administration, the Government and the country will have the great and 
inestimable benefit of his continued advice. 

Thus it will not be for us, as so many of our contemporaries have done, 
to write at this moment of Sir Henry Tanner as having severed his connection 
witli public life, but simply to congratulate him upon the conclusion of a term 
of public service in which he has been not only a conspicuous figure, but 
which he has made memorable by his broad-minded and practical decisions in 
many matters of the highest possible technical moment. Xot least among these 
decisions was the unique one whereby reinforced concrete was introduced into 
Government buildings, regardless of the conservatism — not to^ say opposition — 
that prevailed in this matter both in Great George Street and in Conduit Street, 
the homes of the Institution of Civil Engineers and the Royal Institute of British 
Architects. 

Sir Henr\ Tanner is, as far as Government work is concerned, the pioneer 
architect in England to undertake any really great enterprise with this form of 
construction, but if he was a pioneer in his own department, he was also a 
great leader and most tactful and conciliatory adviser on the many committees 
with which his name was associated which dealt with reinforced concrete. We 
would remind our readers particularly of his chairmanship of the Reinforced 
Concrete Committee of the Royal Institute of British Architects, his office as 

B 2 221 



OUR COMPETITION. [CQNCKETE 



president of the Concrete Institute, his seat on the Reinforced Concrete Com- 
mittee of the Institution of Civil Engineers. 

It is to be hoped that the subjects of concrete and reinforced concrete will 
continue to have Sir Henry Tanner's valuable advice and wise advocacy and 
support. Perhaps with the lesser ties of time he will even be able to g^ive yet 
more time to these subjects in the future than in the past. 

OUR CONCRETE COTTAGE COMPETITION. 

We desire once more to remind our readers of the Concrete Cottage 
Competition which we have organised and in respect to which competition 
designs have to reach us by May 15th, 

Particulars of the competition are obtainable upon written application, and 
we suggest that all directly or indirectly concerned in this important problem 
should use their influence to obtain the co-operation, in this competition particu- 
larly, of the younger architects, to whom the matter of a successful design and 
the publicity that will be accorded it should be of considerable utility. 

Probably over 100,000 cottages will be required during the next few years 
for our rural population, and it is not improbable that both for practical, 
hygienic, economic and local reasons a considerable proportion of these will be 
erected m concrete. 

The interest that has already been accorded to this competition by great 
landowners and their agents, by public authorities and their officials, and by 
the public Press, shows us that there is a very great demand for a suitable 
design. 

The problem is one of the most far-reaching importance, for it affects not 
only the well-being of the rural coimmunity and the tilling of the land, but it 
affects many of the great industries concerned in the cheaper forms of building 
construction, and thus the problem is essentia^./ one of ;^' s. d. 

The reasons for our arranging this competition we have already given and 
we trust that by the 15th May we shall find that our object has been achieved 
by competitors producing designs of real practical utility. As to the prizes we 
offer and the arrangements we have made as to assessors, we would refer to 
our advertisement columns. 



222 



r J , CONy n?l JCTION A L 
[t^ EJMCilNKt-BlNCi — ^. 



CONCRETE MASONRY IN THE PANAMA CANAL. 




CONCRETE MASONRY 

IN THE 

PANAMA CANAL. 

(Conclusion.) 



By JOHN GEO. LEIGH. 



This article is continued from our March issue.— ED. 



Ccncrete has entered largely into the construction of the line by which 
electrical eneroy will be transmitted from the hydro-electric generating station 
at Gatun to load centres at Cristobal, nearer the Atlantic, and Miraflores and 

B;il]}oa, on the 
Pacific side. The 
line runs completely 
across the Isthmus, 
parallel with the 
riglit-of-way of the 
i^mama Railroad, 
and will be used for 
the distribution of 
energy for light and 
moti\e power at the 
terminal docks, 
locks, etc. For this 
line there will be re- 
quired 917 steel 
bridges, having- a 
span between side 
frames of 36 ft., and 
spaced on 300 ft. 
centres. The stand- 
ard concrete foun- 
dation, the type of 
which has been 
carefully studied, 
consists of two 
pedestals resting 
upon a spread slab, 
w h i c h latter i s 
reinforced by 




A. 2,250 K\V. water turbine. 

B. 2,000 K\V. generator. 

C. Reactance. 

D. Generator ins'rument trans'crmers 

E. Generator switches. 

F. Busl. 

G. Bus 2. 

H. Circuit switches. 

I. Cable vault. 

J. Circuit instrument transformers. 

L. First gallery (el. + 40-85). 

M. Second gallery (e'. + .55"35). 

N. Main floor (el. + 33 25) 

O. Low water (el. + 7). 

P. 30-ton crane. 

K. Penstock. 

S. Draft tube. 



/»-..■ J. 



• r^:!-;.:^. 



Fig. 9. Section through Hydro-Electric Station. 
Concrete Masonry in the Panama Canal. 



223 



JOHN GEO. LEIGH. 



iooNc!iJfc:i'li:i 



scrap steel rails. Each leg- of ihe side frame is secured to the pedestal through 
lA\o 15-in. anclior bolts, which are clamped at the lower end tO' the steel rails in 
the spread shib. Provision for anchoring the foundations is made by extending 
downward long reinforcing rods, encased by concrete in a drilled hole, sprung 
at the bottom with light charges of dynamite. 

Exhaustive studies have been made to 
secure at the various locks not only a distri- 
bution (^f lig:ht best suited to the conditions, 
but also adjuncts calculated to satisfy 
aesthetic demands. Finally, after approval 
by the Fine Arts Commission, the type of 
standard and bracket illustrated in Fig. 10 
was adopted for exterior illumination. The 
lamp used is a larg-e power tung-stcn bulb (400 
watt), set in a concrete hood, the standards 
being- alig-ned longitudinally and transversely 
and the lamps spaced on from 50 to 60 ft. 
centres. Both the pedestal and column con- 
tain a large core, which reduces the weight 
and furnishes a runway for the electric 
wires. About 3J yds. of concrete and 750 
lb. of steel reinforcement have been required 
in the construction of each of the standards, 
and of the latter there have been erected at 
Gatun Ivocks 211, at Pedro Miguel 131, and 
at Miraflores 160, some having- single and 
(jthers double-arm brackets. Each double- 
arni bracket, with reflectors, weighs 
apjjroximately 1,612 II)., and the solid ball 
linial, weighing 750 lb., is used to counter- 
balance the weight of the single-arm bracket. 

The single bracket standards are used 
on the centre walls, where the lamps are 
staggered so as \<> illuminate both lock 
chamb<:rs, the double brackets being placed 
on the side walls, where il is desired lo 
throw ihe lighling llux back <jf the chamber 
for a considerable dislanc<'. 'J he refleclors 
are cast <;f concrete and proxidc^d with 
shading hoods, which })rc\(iil llic glare of 
the lamj) filament from j^enet rating along 
the axis of the Canal. Ihv, entire rcllccloi-, 
with lamj) and so<l«;t, is waterproof and 
fitted to resist in (-xcry r(,'spr( t !r<)pi(al 
deterioration. 

The lamps in the oj>eraling tunnels and 
machine rooms in the Unk walls arc also 

224 




\•>^i. 10. Reinforced Concrete Lamp Standard 
and bracket. 

CoNCKKTK Masonry in thk Panama Canal. 



y, CTQN.S runiri lONAl 
<iL KNdlNKI-RlNlV — 



CONCRHTH MASONRY IN THE PANAMA CANAL. 



j)i()\i(K(l Willi spccialK dcsii^nrd (onciclc icllcclois, .ind iccfii! cNpciiiiU'iit s h:i\L' 
ijDiH' far to (Icnvonsl rale llic clliciciU'N ol ihc arraiii'Cincnl s wliicli lia\c been 
a(l:)|)!t'(l. In llu- liinncl lij^litin^- the j^rralcst trouhlc was orcasioiuci by tlic \u\\ 
hicad-iooin of ~ It., wliich ma(lt> it din'irult i:) secure unilorm illuininalioii at the 
iloor line. This ohstaele has l)e( n oxereonve I)\ pjac in<^' ceiling" lamps on 15-I1. 
eenlres alon^ llu* loni^itudinal axis ol the tiuinels, and 1)\- ])r()\ idinj^" them with 
rcllecHors of c'omparat i\ elv simple desij^n eonsistinj^- of inclined surfaces at the 
four sides. In the machine rooms it was necessary l(^ dej)end u])on side-wall 
illumination, for which i)urpose recesses were cast in concrete at alxjut 
the level of the eye, and the efforts of the designers were directed towards 
shadiuLj' direct rays from the eye without di;triment to the effectixe li^^htin^ of 
the machines. The solution armed at, illustrated in hi}X^- 'i ^m^' •-, ^^^'^ t'> set 
the lamp socket in the U)\) of a concrete rellector, ^Touted into the wall recess, 




isw 



^i=^m^^i^^^^^^^m^^^ 



'^ /■■a^^ii^ : 



m 





1 ,1 1 M u I.I i vl'i-i-L Jlitx .■■■•. . :. vi • V * .• • ♦ •« . >, -• ^.' :■• x--^' 



vv.'/jp-/-; 



■i;:^=:\:fi;i^7^ 



"V.*- 







A. Concrete reflector for ceiling lamps. B. Ktflector for wall 
lamps. C Chase for wiring. D. Cylindrical valve machine. 

Fig. 11. Operating Tunnel in Lock Walls. 



B. Reflector for wall lamps. 
C. Chase for wiring. 

Fig. 12. Detail of Tunnel Reflectors. 



Concrete Masonry in the Panama Canal. 

the wires being br;jug;ht to the lamp through a chase in the wall. In front of the 
lamp is placed a concrete shade, containing a semi-circular opening at the 
bottom, and adjusted in a vertical plane so as to cut off the direct glare of the 
filament and permit the lighting flux to penetrate through the opening and flood 
the m.achine. There will be altogether 2,041 tunnel reflectors — 952 at Gatun 
Locks, 412 at Pedro Miguel, and 677 at Miraflores — and 4,751 machine-room 
reflectors, thus distributed — Gatun 1,524, Pedro Miguel 1,126, and MIraflores 

CONCRETE ARCHES AND WALLS AT LOCKS. 

To the future traveller through the locks few features of the construction 
of the latter will appear more pleasing than the arches at the south end of the 
chambers, connecting the w alls of the locks proper with the guide and flare walls 
of the approach. They are light and graceful in appearance and provide an 
agreeable contrast to the necessarily plain and massive walls of the lock 
chambers. In each flight the purjx>se of these arches is the same, namely, to 
serve as a bridge over which the electric locomotives will pass when towing a 



22 



JOHN GEO. LEIGH. 



[CQNCBETEJ 



ship llirouj^ii 1 he locks. At Pedro Miguel ihe side wall arches, illustrated in Figs. 
I :; and 14, make a continuous bridg:e from the main lock walls at elevation 92 ft. 
above sea-level to the win^- walls at elevation +67 ft. The upper arch contains 
about 1.093 cub. vards of concrete and the lower about 1,021 cub. yards, while the 
arch in the centre wall contains about 1,850 cub. yards. There are in each side 
wall arch about 27,676 lb. of reinforcing steel — 60 bars i^ in. square and 92 
and 82 ft. long, while the centre wall contains reinforcement weighing 47,100 lb. 
The width of the arches in the side walls is 31 ft. and in the centre wall 54 ft., 
the length of span of each arch being 79 ft., the minimum thickness of crown 
5 ft., the radius of intrados 90 ft., and the rise of arch 9 ft. 2 in. 

Owing to the character of the foundation, a portion of one of the southern 
guide walls at Gatun locks differs in construction from that of other similar 




Fi^^. 13. Pedro .Mit^uel Locks, showint4 Outlet in East Wall and Construction of Lower Main Gates. 
CriNCRKi K Masonry in thk Panama Canal. 



works along the Canal line. The wall extends into the Lake 1,500 ft. from the 
upper guard gates, and the south, or outermost, 850 ft. rest on light earth, 
bed rock being al)r>ul \ ^o It. below the surface. This j)()rtion, therefore, is 
constructed upon j/iles dri\<n Iroin 35 ft. to 70 ft. into the groimd ; and to 
reduce the weight on lliem a., miK h as possible the wall takes the form of 
a reinf.'jrced contrvie ( cllular sirndure. The wall is foimded on a concrete slab, 
from 4 ft. U) 5 ft. thick, laid o\cr the t<;[)s of tlu; piles, and is 58 ft. wide and 
67 ft. above ihe ground, ulii( h is here 1,2 ft. aboxc s<'a-le\'el. The outside shell 

226 



J, tTON> TDWCTIONAI 



COSCRETE MASONRY IN THE PANAMA CANAL. 



is ;i itiiilni ci (1 concn-li' wall, j ll. illicit, wilhin wliiili arc l\\o iS-iii. \\ails 17 fl. 
a|);n't, runninj^ ihr Iriii^th ol tiu- jliukIc wall, and lill\ walls ol llu,' sainr 
tliii^kiu'ss (M'ossiiii^ lioin side lo side at ici^ulai' iiitcr\als of 15 ll. I luis the 
iiitt'iioi" consists ol a scries ol cells, 15 It. 1)\ 17 It., separated by i8-in. 
partitions. In tlic ccllulai- ])oiiion ol the wall about 35,000 cuIj. yards of 

c-oiu'iH'tc ha\'e been jilaecd. 

Modifications of the j)revailin^ method of construction have also to be 
noted in (M)nnecti()n with the lower apj)roac^hes to the locks. 'liie uj)j)er 
apj^roach walls loi' all the locks are of reinforced concrete in cellular structure, 
but for the lower walls at (iatun and .Mirailores — with a view to avoiding- any 
]).)ssibility ol (\)rrosi<)n ol the steel reinforcH-nient b\- sea water onh- mass 




^WWW^" 



B. Uin sq. Bars 12 in. cC- F. 12 in. Drain. 

D. Cross drain. G. Caisson se.nt. 

E. 45° Slope. 11. Lower guard gate sill. 

J. Caisson sill, 



Fig. 14. Side Wall Arches, Pedro Miguel Locks. 
Concrete Masonry in the' Panama Canal. 



concrete has been used. At Gatun the desirability of variation was enhanced 
by the relatively insecure foundation, for, after excavation had been carried 
50 ft. below sea-level, the use of long piles was found necessary to reach rock, 
in some places 50 ft. further below. The structure planned to meet these 
conditions and replace the heavy U-section, double g-ravity walls at Pedro 
Miguel and Miraflores consists of a series of piers, connected by flat spans 
above, forming a causeway of successive bridges. To protect them against 
transverse sliding, the piles, which are driven on 4-ft. centres, longitudinally 
and transversely, and on 3-ft. centres for the outermost 200 ft., are surmounted 
by a continuous base of concrete, extending i ft. below the top of the piles. 



227 



JOHN GEO. LEIGH. 



rCQNCBETEJ 



This base is 58ft. wide. The l)ott()m is level, but the top is a series of 
inverted stepped arches, described on a radius of 42 ft., the haunches between 
which form the bases of the piers of the flat-span bridge. At the lowest step of 
the arches the thickness of the base is 5 ft. 7 in., but at the springing- line it 
is 3 ft. more. Reinforcement in the base consists of twenty continuous 
longitudinal rows of 70 lb. rail, resting on the top of piles, and duplicate rows 
of similar rail 4 fl. h in. higher up. The side elevation of the base and of a por- 
tion of the completed wall is illustrated in Fig. 16. 

Fig. 17 is a transverse section of the wall. Each pier, it will be noted, 
consists essentially of two piers, connected by a semi-circular arch. The hori- 
zontal normal section of each com.ponent is 18 ft. by 10 ft. ; the inner sides are 




Fifi. 15. Construction of the North Approach Wall, Pedro Mif^uel Locks ; view showinf^ method of 

l)lacinfi concrete. 

Concrete Masonry in the Panama Canal. 



verlica] f'^r a JKtighl of 22 fl. 5.I in., this point above the base being the spring- 
ing line (jj the arch. On tjic oulcr faces ihe piers are vertical from the base, 
at ell-Nation — 39'44, to the loj), which is u ft. above sea-level. The piers, twenty 
in number, are set 50 ft. a|)art, cen1r<- to centre, the sj)ans (M)nnecting them being 
carried bv four 0-ft. and six 4-ft. h-\n. plate girders, encased in (M)ncrete. To 
prcN'ent water from surging from one aj)proa(^]i (Oiannel to the other, when a 
lo<^k chamber is dis<'harging, the six spans of wall nearest the k)cks are closed 
by 26-ft. curtain walls. 'Ihe wall ext<n(ls i,oiO ft. from the line of fender 
chains, and contains about 45,(xj(j cub. yards of concri'te. 

The corresponding struiture at .Mirailores, extending into the I'acific 
entrance channel, takes tlx foi in of two walls, back to ba(^k, with a space of 

228 



rTTcoNSTiaTri lONAi 



CONCRETE MASONRY IN THE PANAMA CANAL. 



5 ft. hitwicn hasi's, and witli fares in rontiiuialion of \hv centre wall. The 
outer ciuls are joined by a concrete wall, H ft. thick, perj)endicular to the 
parallel walls, and ihe si)ace thus en<^lose(l is filled with rock and screenings, 
the deckino- hcin.L; laid oxer llu' lop. This striK lure, whicii contains 82,000 cuh. 
\ar(ls of concrete, differs fioin tlie lower ai)j)roa(-h wall at I'cdro Miguel in 
that the hasi's of the |)arallel walls do not touch and that each of these walls 
rests on nx^k, with a toe alon^- the outer side about 10 ft. wide at base laid in 
excavation carried to elexation -50 ft. From the ed^^e of the to€ the wall 
bailers inward, 1 on j, to a height of 9 ft., and from this i>:)int rises 
verlicallv for 54 ft., a few inches at the top battering inward, i on 3, to form 
coping. The rear, or inner, sides of the walls are stepped in, at intervals of 

6 ft., from a thickness of 26 ft. 6 in. at base to 8 ft. at top. Corbels, supported 
on the steps 6 ft. and 12 ft. below the top, project inward to a distance of 14 ft. 
from the face of the wall, to support the superincumbent decking and electric 
locomotive lowing rails. At Pedro Miguel the wall is of mass concrete for 
950 ft. from its juncture with the centre wall, the remaining 250 ft. being of 
reinforced concrete. 

DETAIL COST PER UNIT OF WORK. 

Not the least interesting and valuable record of the activities of the Canal 
Commission will be found in the reports of the Cost-Keeping Accountant. The 
cost reports compiled prior to January ist, 1910, included comparati\ ely little 
detail, except for excavation work, and were not available until five or six weeks 
after the close of each month, nor did they contain any charge for plant 
and equipment, such expenditures being carried into the accounts in total only. 
With the cummencemeni of concreting, however, it became apparent that some 
method should be adopted by which the sums expended in developing quarries 
and sand pits for the production of material and in providing mixing and other 
machinery would be absorbed in the cost of the product, to the end that all 
expenditures incurred for preliminary work, machinery, and installation would 
be taken up in the cost of the masonry. 

Consequent upon recognition of the importance of such measures, a cost- 
keeping system was devised which has provided a uniform classification in the 
various construction divisions, identical items of expense entering into the cost 
of each division for work of like character. A system of arbitraries, revised 
semi-arnually when necessary, was also adopted with a view^ to the absorption 
into the construction cost of all expenditures for plant and equipment, based 
upon the estimated cost and the estimated amount of work to be accomplished, 
and wholly ignoring any salvage w^hich might be realised after the completion 
of the latter. In order, also, to state the accounts uniformly, the plant 
arbitraries were applied to all construction work prior to the date on which the 
system became effective. 

By means of this system complete control has been obtained over expendi- 
ture for labour, material and services. The labour costs have been prepared from 
the daily reports of foremen in charge of the gangs, and balanced against the 
monthly pay rolls, and the costs for material have been obtained from the orders 
drawn on the storehouses, balanced against the chief quartermaster's reports of 
the value of material issued. Sand, stone and cement have been priced at the 

229 



JOHN GEO. LEIGH. 



ICaSCWTF] 







cost of delivery at the ware- 
houses or storag-e piles, the 
prices of the two first being 
based upon the n-;onthly 
output and the expenditure 
connected therewith. The 
price at which the material 
has been charged into the 
vv'ork is the average result- 
ing from the cost of the 
quantity left in storage at 
the close of the preceding 
month and the cost of pro- 
duction during the month. 
In the detailed statements 
of costs all expenses are in- 
cluded other than the pro- 
portions representing ex- 
penditures for sanitation, 
hospitals, civil government, 
lands purchased, terminal 
docks and wharves, reloca- 
tion of the Panama Rail- 
road, purchase of steamers, 
construction and repair of 
buildings and municipal 
improvements in Panama, 
Colon and the Canal Zone. 
The total amount of 
concrete laid during the 
fiscal year igio-ii was 
1,742,928 cu. yd., distri- 
buted as follows : — Gatun 
Locks, 911,137 cu. yd.; 
Gatun wSpillway, 59)^51 
cu. yd. ; Central Division, 
1,020 cu. yd.; Pedro Mi- 
guel Locks, 498,187 cu. yd. 
and Mirafiores Locks, 
272,933 cu. yd. Taking 
into consideration differ- 
ences in the length of the 
working day, the average 
amount of masonry placed 
daily in the locks by 
the Atlantic Division was 
^^^^573 *'-'• yd., and by 



230 



g^^5^!yl^^^ CONCRETE MASONRY IN THE PANAMA CANAL- 



.pMOHMt-I-J^lNti- 



llu' Pacilic- l)i\ision j<Srj(j(j cu. yil. I he cost pw cu. }(1. ;il (iatiin Locks 
was vS().5()i(), al llic Si)ill\vay $6.7044, al IV'dro Mij^ucl Locks $4.7040, and 
al Mirallorcs vS4.()82(). Al (iatuii the use of 7^^,609 cu. yd. of lar^c rock 
Resulted ill a sa\in«^- of $o.2(SS.S pvr cu. \(1. of inalcrial j)lacc(i. 'llu; cost of 
stone in bins al (iatun was $2.3403 j>cr cu. \(1., and in lli-c storage pile for 
llic locks on liio Lacilic side $0.8443 per cu. yd. Crushed stone from Porto 
Hello was lransjx)rti\l to (ialun by barges, and unloaded by cableways and 
derricks, while from .\ncon c|uarry the crushed rock was carried b\ rail to 
storage and dumped from Iresllc^s. '1 he difference of $0.7184 in the cost of 
these two methods deducted from the actual cost in storage left $.1.3219 per 
cu. yd. as llie unit cost of Porto Bello stone at (iatun. Sand for the locks 
on the Pacific side was secured at Chame, in the Bay of Panama, towed tw-enty 
miles, unloaded by electric cranes, and delivered in storage at a cost of $1.8565 
per cu. vd., while sand for Gatun was brought fn^m Nombre de Dios and 
unk>aded by cableways. Omitting the cost of transportation from the sand- 
banks to the docks, the cost to the Atlantic Division was $1.3172 per cu. yd., 
and to the Pacific Division $o.(xdi5. Taking into account the various con- 
ditions, the year's operations showed a difference in favour of the Miraflores 
Locks of $1.7340 in the cost of cement, sand, stone, and large rock; of the 
Pedro Miguel Locks in respect of other items which went to make up the cost 
of the finished product — e.g., forms, placing-, pumping, power, repairs, plant 
arbitrary and division expenses, and of the Atlantic Division in mixing and 
reinforcement. 

There were placed in the locks and spillways during 1911-12 1,443,570 
cu. yd. of masonry. The unit costs of this work were : At Gatun Locks, 
$7.7552; at Gatun Spillway, $7.0988; Pedro Mig-uel Lock, $6.4640; and Mira- 
flores Locks, $4.7675. Thus, with a decrease of 512,315 cu. yd. laid in 
Gatun Locks, the cost of plain concrete rose $0.5398 per cu. yd. as compared 
with the previous year. At Pedro Miguel, also, where the amount laid was 
less by 363,609 cu. yd., there was an increase in cost of $1.0143 per cu. yd., 
due to forms, placing, mixing and arbitrary. On the other hand, at Miraflores, 
where the amount placed was 456,163 cu. yd. greater, the cost of plain concrete 
was $0.0959 l^ss. The labour costs for the year per cu. yd. were lowest at 
Miraflores, namely. So. 8394, Gatun Locks coming second with $1.3840, Pedro 
Miguel Lock third with $1.4733, and Gatun Spillway next with $1.5425. The 
difference between the costs in the Atlantic and Pacific divisions mav be attri- 
buted mainly to the cost of cement, sand and stone. The cost of stone at the 
storage piles at Gatun was $2.4952, as against $0.7996 per cu. \ d. in the 
storage piles for the locks on the Pacific slope. If, however, there be deducted 
from this dift'erence of $1.6956 the extra expense attached to the Porto Bell'j 
stone, represented by the difference ($0.7365) between the costs of towing and 
unloading and those of transportation by rail, together with the difference in 
plant arbitraries, amounting to $0.4336, it will be found that the net dift'erence 
in labour costs in favour of Ancon quarry was actually $0.5255 per cu. yd. 
Sand procured from Xombre de Dios and from the Chagres river beds cost 
respectively $2.2414 and $1.2850, delivered at the stock piles of the Atlantic 

231 



JOHN GEO. LEIGH. 



ICONCBETEl 



Divisi(3n, as compared with So. 7025, the cost per cii. yd. of the sand gathered 
at Chame and towed to Balboa. 

ANALYSIS OF CONSTRUCTION EXPENDITURES. 

The classified expenditures of the Canal Commission to December 31st of 
last year amounted to ;^,'(x|,892,io5, of which about ^^40,442,865 was appor- 
tioned to the Department of Construction and Engineering, ;^i8, 41 3,000 to 
** general items," ^3^479'450 to the Department of Sanitation, and ;6'i,395,ooo 
to the Department of Ci\'il Administration. From the latest available state- 
ment of details 
(that to Septem- 
ber 30th) of con- 
struction expendi- 
tures, amounting- 
in the aggregate 
to ^.^40,670,000, I 
note the following 
particulars : — 

Excavation and 
dredging of Canal 
prism : From and 
including Gatun to 

the sea, 39»9oi.7,53 
cu. yd., cost 
^^2, 1 18,330; from 
Gatun to Pedro 
Miguel, 109,624,594 
cub. yd., total cost, 
including masonry 
and ;^,"i 5,600, value 
of plant and equip- 
m e n t to be ab- 
sorbed in construc- 
tion costs after 
September 30th, 
p£, 1 7,r)9o,ooo ; from 
and including 
Pedro Miguel to 
the sea, 45,228,233 
cu. yd., total cost 
^,3,000,000. 
(iaiun Spill\\ay : Excavation and ])ic|)ariiig foundations, 1,588,921 cu. yd.; 

masonry, 229,873 cu. yd., cost ^'377>""^^ i">'' <''>^' VS7.954S; ironwork, gates 

and <jp<;raling- machinery, ;673, 235 ; lolal cosl, ^.'700,000. 
Gatun Dam: 'JV>tal cost, ;^'i ,783,00(3. 
Gatun \j)<:ks : Cost of excavation and |)rc|)aiing foundations, iiK hiding 

83,670 lin. fl. concrcli piles, ^.'934,800; mass masonry, 2,041,156 cu. V(l.» 
232 




Viti- 17. Sectional View of Dual Pier. 
Conc:kktk Masonkv in tiii-: I'anama Canal. 






CONCRETE. MASONRY IN THE PANAMA CANAL. 



cost ^>^, I '^q, J 17, unit Ci)s\ $7,451)1 ; iiiiisoniy used in iiist;ill;il ion ol in.iclniUTy, 
2^,011 (U. \{1., cost /v'\^,^^57, unit cost ^ij.^Sj.S; total cost, iiu ludiii^ J4:i^<^'^> 
fender cli.iins, opnatini; niacliinir\ , etc., ^,5,000,000. 

(iaiiiii li\ (Iro-clcct lie station and plant : Cost ^.'J5,000. 




Fif4- IS- Laying Concrete, Gatun Upper Locks ; view from a centre wall culvert. 
Concrete Masonry in the Panama Canal 

Gatun to the sea : Total construction cost, including ;£'58,670, plant to be 
absorbed in construction costs, ;^Ji 1,324,000. 

Pedro Miguel Dams: 1,567 cu. yd. masonry, unit cost $5.3872; total cost, 
i.-'/S'-^oo. 

Pedro Miguel Locks : Cost of excavation and preparing foundations 
^^311,560; mass masonry, 906,55^ cu. yd., cost ;£!"i ,099,600, unit cost S5.8838; 

233 



JOHN GEO. LEIGH, [CQNCBETFJ 



masonry for machinery installation, 14,576 cu. yd., unit cost $11.9716; total 
cost, including- operating machinery, etc., ;^2,4i3,ooo. 

Miraflores Dams and Spillway: Excavation, 159,130 cu. yd.; masonry, 
yy,92=^ cu. >cl., cost ^.'108,405; total cost ^£^384, 220. 

Miraflores Locks : Cost of excavation and preparing foundations, 3,286,800 
cu. yd., ^671, 585; mass masonry, 1,479,079 cu. yd., cost £,'1,634,483, unit cost 
S5.3596; masonry for machinery installation, 16,984 cu. yd., unit cost 
Si 1. 541 1 ; total cost, including iron work, gates, emergency dams, operating 
machinery, etc., £"3,45^'330- 

Pedro Mig-uel to the sea : Total cost, including- excavation and part con- 
struction of the abandoned locks and dams at La Boca, construction of the 
Xaos Island breakwater and about £200,000, value of plant and equipment to 
be }et absorbed, £"9,800,000. 

Terminal facilities at Cristobal : £"18,360. 

Terminal facilities at Balboa : Part cost, including £'57,275, value of plant 
and equipment to be absorbed, £^667, 470. 

Miscellaneous items : Permanent town sites, Balboa, La Boca and Pedro 
Miguel, permanent buildings, power transmission line, trans-isthmian oil-pipe 
line, and lights and buoys, £202,000. 

In the final quarter of the financial year 1912-13 the cost per cu. yd. o^ the 
masonry placed in the several locks was as follows : — 

Gatun. 
$ 

Concrete 6'i2o8 

Administrative and general expense ... '4444 

Total cost 6-5652 

Reinforced masonry 9'i382 

Administrative and general expense ... 1-0252 
Total cost 10-1634 

The exceptionally high cost of masonry during this quarter was due to 
charges for finishing work, clearing the kx:k floors, etc., these special expenses 
being proportioned to " Wood forms," " Mixing," and " Placing." 

The progress, month by month, of masonry construction at the various 
locks is indicated in llie foHowing tables : — 



edro Miguel. 


Miraflores. 


$ 


S 


93-4848 


7-7140 


9-8458 


I '4693 


103-3306 


9'i833 


14-4834 


9-7500 


3 "3 1 65 


2'o55i 


17-7999 


11-8051 



Gatl'N (cu. yd.). 



1900. 

January — 

February — 

March — 

April — 

May — 

lune — 

July — 

August 1,298 

Se[;temljer 12,294 

October 29,378 

Movember 3o,2 7(j 

December 42,832 



igio. 


1911. 


1912. 


1913- 


54,136 


72,919 


34,983 


28,085 


55,696 


72,103 


26,664 


30,780 


60,998 


86,884 


27,532 


48,180 


63,227 


67,361 


11,600 


22,732 


74,273 


67,844 


7,746 


13,046 


8(),40i 


55,035 


6,095 


5,509 


84,001 


71,046 


8,093 


3,431 


85,686 


66,928 


6,855 


6,258 


76,720 


57,298 


3,162 


442 


86,949 


53,636 


3,252 


174 


75,152 


43,907 


6,02() 


280 


80,212 


43,590 


5.697 


120 



Total 116,072 886,451 758,821 147,708 159,037 

Grand total 2,068,089 



11 , CON.S rm K "IION A I . 
^KN(.lNKl-klN(. --. 



CONCRHTH MASONRY IN THE PANAMA CANAL. 



I'KDKO NlKilKI. (cu. \ d.). 



j;inuar\' 

l'"i'l)ruar\ 

Marrh ." 

April 

May — 

Juiu' 

July 

August 

SeptemhtT -2,.i70 

Ottober ^,310 

.\(»vember io,i6q 

Uecember 13,007 



13.-J18 
i8,7()3 

20,576 
.K'.63i 
4i,4()4 
5 1, 264 
50,702 
61,422 
64,248 
42,834 



Kjl I . 

38,513 
37,011 
44,716 
28,635 

ig,i35 
18,243 

iy,(jo6 
20,736 
15,370 
25,637 
10,622 
14,360 



Total 33,856 444,047 30i,8o3 

(".rand total 023,438 



igi 2. 

15,003 

12,630 

0,331 

0,460 

10,736 

10,061 

1 1 ,480 

5,005 

3,030 

6,587 

7,972 

6,958 

100,261 



I0I3- 
4,652 

4,204 
13,412 

2,145 
1,144 

773 
1 ,820 
1,884 

1,144 
412 
630 

1,162 

33,481 



MlK 



1000. 



January 
l""ebruar\- . 
March .... 
April 

May 

June 

July 

August 

September 

October 

November 

December 



Total 

Grand total 



Fl.OKKS (cu 


yd.). 






1010. 


lOii- 


1012. 


1913- 





24,018 


48,416 


50,456 


146 


20,8g6 


63,893 


34,979 


314 


31,173 


83,706 


21,030 


13 


38,758 


97,735 


13,266 


27 


36,154 


92,005 


6,056 


1,603 


26.536 


68,398 


3 836 


3,672 


32,840 


66,026 


3,810 


6,030 


57,003 


75,388 


3,643 


18,133 


56,083 


46,122 


1,907 


22,159 


60,873 


54,790 


1,152 


23,871 


41,726 


39,874 


2,007 


21,533 


48.772 


46,746 


1,859 


07,501 


474,832 


783,180 


144,901 




1,500,525 







CONSUMPTION OF CEMENT. 

In view of the impending commencement of lock construction work what 
is probably the largest single order ever given for furnishing Portland cement 
was awarded in January, 1909. This called for the delivery, f.o.b. New York, 
of 4,500,000 barrels, at a minim'jm rate of 2,000 barrels and a maximum rate 
of 10,000 barrels a day, ullh the right to increase the order 15 per cent. On 
this contract the Atlantic Division received 1,343,757 barrels in wood up to May, 
191 1, when this method of shipment was changed to bags, as preferred bv the 
Pacific Division from the commencement. 

During the period of greatest activity in lock construction the delivery of 
cement from the United States amounted frequently to 7,000 barrels dailv, and 
a stock supply of from 100,000 to 200,000 barrels was maintained on the 
Isthmus to provide against delays in shipment. La^er, however, the rate of 
delivery was gradually reduced to about 1,500 barrels a day, a reserve being 
maintamed of approximately 50,000 barrels. In September, 1912, tenders 
were opened for the supply of an additional 1,000,000 barrels, or of 30 to 15 per 
cent, more or less at the option of the Commission. The specification also 
provided for delivery up to July ist, 1913, of from 2,000 to 5,000 barrels a day. 



JOHN GEO. LEIGH. r— 

and thereafter until the completion of the contract, of from 500 to ,,000 barrels 
Together w.th two tenders from other companies, a letter was ;;ceiveQ from 
the former contractors offering to continue deliveries as might be eededto 




complete the u<,rl< on ihc Ca,,;,! ,„ Iho pric- ,j. ,,,,„ ,,,, ,,,„,.,.| „^, ,,^,| 
earhcr contract; and ,h,s olfc-r w.,. ac,<.pu.,l by Ihc Secretary of War 
recommendation of tlic Chainnan „f ihc ( ■ornmissicn. 



ing Ihc 
on the 



^3'^ 






RECENT BRITISH PATENTS. 



RECENT BRITISH PATENTS 
RELATING TO CONCRETE. 

Wc Pr^wose to present jUritcrvjls pjrttaiUrs of British Pjtents issuea^in connection 
^ coru-nTe Inr reinforced concrete. Tt^e Ust article appeared m our tssue of 



'With 

October, /"/J. ED. 

Column Moulds. Su. 5,037/13. Blaw Steel 
Conslnation Company. Accepted Sovenibcr 20/13.— 
This iuvciiLiou is applicable lo the formation of all 
kinds of concrett' structures circular in cross s^-ction, 
whether solid or hollow. 

The invention refers particularly to moulds in 
w hich the shell is composed of a number of segmental 
metal body sections adapted to be assembled together 
into circular formation, this shell being adjustable 
to diameter by varying the number of sections used. 
The invention also comprises improved means for 
varying the length of the mould, for stiffening the sheet 
metal plates employed in the construction, and for 
makinii them conform to substantiallv true circular 
form. 

The form or mould {Fig. 2) consists of two tubular 
sections, the lower of which extends from a to b and the 
upper from c to d, but of course as many sections as 
are necessary may be employed. Either section {Fig. 
i) is made up of four segmental plates (i, 2, 3 and 4), 
the plate 4 being a filler plate narrower than the others. 
The plates are provided at their vertical edges with 
outstanding flanges 5, the flange of one plate abutting 
against that of the adjacent one. Extending circum- 
ferentially of the plates i, 2, 3 and 4 are a number 
of stiftening bands, consisting of substantially arcuate 
rigid metal plates set edgewise, which serve also to 
give true circular shape to the columns. This circular 
band is adjustable to diameter. 

Fig. 2 shows two stiffening bands, though any 

number may be used. As shown {Fig. i) the band is 

made up of four sections (6, 7, 8 and 9), though any 

number may be used, depending on the size of the 

mould and number of plates used. The sections overlap 

and extend through slots in the opposing flanges 5, 

10 and 1 1 being the overlapping edges of the sections 8 

and 9. The overlapping edges of the stiffening ring sections are provided with slots 

12 which receive the wedges 13 lying on opposite sides of the vertical flanges 5. 

When the wedges are driven downward they apply tensien to the sections 8 and 9 and 




Figs 1 & 2. Column Moulds. 




e of czf 

Figs. 1—4. Connections for Metal Reinforcement 



C 2 



237 



RECENT BRITISH PATENTS. 



also press the opposing faces of the 



[CQNCBETFJ 




Fif^. 5. Connections for Metal Reinforcement. 



the number of plates employed the 
diameter of the columns formed ma\ 
be widely varied. 

The plates i, 2, 3 and 4 are made 
of relatively flexible sheet metal, and 
the stiffening numbers 6, 7, 8 and 9 
give strength to the mould and also 
make it conform to an approximately 
true circular cross section when the 
stiffening bands are applied. The ten- 
sion applied by the wedges forces the 
flexible metal to conform itself to the 
inner surface of the bands. A set of 
stifl'ening bands is provided for each 
diameter of column, such bands being 
accuratelv formed to the desired radius. 
The bands should be divided into as 
few sections as is possible without 
interfering with the freedom of remov- 
ability of the parts. 

In manufacturing the form, the 
segmental plates are first cut to the 
proper dimensions, next the slots are 
punched in the edges, the plates are 

then rolled to a given curvature and the flanges are then bent back. By this method, 
using automatic machinery when possible, the plates will be exactly alike. 

When two lengths of tubular section are used together distance pieces 16 of wood 
mav be employed if any unusual strain is to be imposed on the upper section; ordinarily 
they will not be necessary, as one section 
clamps the other securely at the intergaging 
telescope ends. 

Connections for Metal Reinforcement, — 

— No. 2,945/13. G. W. Stokes. Accepted 
December 18/13. — I his invention relates to 
the method of connecting the metal rods or 
bars used in reinforced concrete constructions. 

In the usual method adopted, when there 
have been two or more rods or bars of iron 
or steel running longitudinally through the 
concrete beam, either with or without 
stirrups, shear members or ties, it has been 
ffjund that the dej)Ositing and ramming of 
the concrete has displaced the rods in relation 
to one another and in relation to the outside 
face of the concrete. 

In some cases the rods have been bound 
together by tying, soldering, clani|)ing, or 
other means, but this has reduced the area of 
the metal surface available for adhesion to the 
concrete, and caused the metal to l)c less 
evenlv distributed over the cross section of 
the concrete nn-mb^r. 

This invention provides an improved 
adjustal>l<- and rigid lateral connection be- 
tween two or more longitudinal bars in a 
r<'inforr<'d concret<' Ixani, which will keej) 
them at the correct distance apart and also 
at the correct distance from the face of llie 
concret(; member, and will also prevent tli( ii- 
displacement during the depositing and rannning (jf the concrete. 

23« 




i?- 



a 




I'iiis. 1-3. 

Anjrsi Aiii.E Stirkui'S for Ricinforckd Concrete. 
Constructions. 



J,c16NM^>^)c■naNAl. 

< V KNdlNKl-PlNd — 



RECENT BRITISH PATENTS. 



riif irucntioii c'(»ii>i>l> in [\\n oi moii' links cuh sin roundiiij^ two or more bais, 
at rij^lil .iiij^Ics to the direction of their length ;nul at suitable points, and of two or 
more wedi^es, each (hixcn between the two bars with or without distanc(; pieces placed 
betwcvn the bais. h'-ach loo|) is fornu.'d b\' bendin^^ a iiKtal rod of round or other 
suitable section round a }4;roup of two or more lonj^itudinal bars, j)laced in the exact 
|)osition whiih they are desij^ned to occupy in the reinforced concrete beam, or bv 
bendiiii; the metal rod round a template, the cross section of which is of the shajje 
enclosed by a llexible thread j)assed round the outside of the j^roup of bars at rijjfht 
aiii^les to the direction of their lenj^th. 'I"he ends of the loops thus formed are con- 
nected to«iether by W(ldin<4, twisting, or crossinj^, and may be continued into the 
concrete to act as ties, slirrujjs, or shear members; or they may be bent round another 
i^roup of i)ars, or the ends of the loop may be continued until they reach the outside 
face of the concrete member, to form short struts between the bars and the moulds, 
thus retainin<4 tlie bars at the correct distance from the moulds durin<:f the depositing 
and rammino of the concrete. 

Fig. I is a cross section, Fig. 2 a side elevation, and Fig. 3 a perspective view of 
portions of two round longitudinal bars (a) embraced by a loop (b) and spaced bv a 
driven wedge (c) which locks the bars and forms the combination into a rigid frame. 

In Fig. 4 the loops (6) are bent round, or slipped over the four bars (a), while their 
ends (h) are extended or bemt to form short struts restin^^ on or against the timber or 
other mould. The distance pieces (J) are short lengths of square bar to fit convenientlv 
between the rectangular bars (a). The wedges (c) are short tapering lengths of flat 
steel driven diagonally between two of the bars (a). 

^'^'- 5 shows an application of the invention to beam reinforcement. Twc 





•J ^'--t +:■ 



\ — r 




Figs 1^3. Reinforced Concrete and Similar Structures. 



239 



RECENT BRITISH PATENTS. 



[CQNCKETE 



longitudinal bars (a) are rigidly connected and 
retained at the required distance apart by 
loops (b) and wedges (c) and together form a 
unit of two bars. A second pair of bars (a') 
form a similar unit and the two units are 
rigidly connecti^d by loops {h') and driven 
wedges (c') and thus combined form a unit of 
four bars. 

Adjustable Stirrups for Reinforced 
Concrete Constructions.— ^o. 15,667/13. 
.1. .1. Storey. Accepted Xovember 27/13. 
— This invention relates to an improved 
adjustable stirrup which can easily be 
threaded on bars with rough ends or (as is 
often the case) on bars which vary consider- 
ably from the standard sizes. 

The stirrups are also locked on the bars 
in such a manner as to be practically im- 
movable under the rough usage of ramming 
the concrete. 

The stirrup h, Figs, i and 2, has its legs 
formed tapered with a terminal loop en- 
circling the main reinforced bar a; clips (c) are 
placed on the tapered legs and driven down 
tightly, their final position depending on the 
size of the bar a, and therefore allowing some 
variation in the latter. In Fig. i there are 
shown clips in the three positions they would 
occupy respectively for bars of standard size 
or slightly above or below it. 

The loop of the stirrup may be round 
or of suitable shape to correspond with the 
bar on which it is placed, while the stirrups 
themselves may be either straight or bent as 
shown in Fig. 3 and used in any desired 
combination. 

Reinforced Concrete and Similar Struc- 
tures. So. 25,140/13. /. R. Givyther. 
Accepted November 3/13. — This invention -* '• 

relates to reinforced concrete and similar fireproof structuptes in which tiles, blocks or the 
like are used to replace shuttering. The invention consists in an improved method of 
keving together such tiles, etc. ; they are formed of sections provided with projections, 
preferably dovetailed, on the concrete face, such projections engaging with corresponding 
ones on the section below. 

Fig. I shc)ws the application of the invention to a rectangular column with beams 
running .into it. The tik-s or blocks (a) ar<' provid<'d with dovetail projections (c) keying 
into the core, and are held together by a metal strap at the vertical joints. 

The beams running into the columns consist of moulded channel-shaped tiles (a) 
with similar dovetail [)rojertions (c). The invention is aj)j)licable also to the ordinary 
fireproof covering of buiU-uj) s1<'el sections. Figs. 2 and 3 show the application to a 
concrete buttr<'ss prcjvickd with metal r<'inforc<'ment. Single trough-shaped tiles (a) 
with projections (c) ar<' employ<'d at s<'Ctions .s- .v, z — s, two such sections placed mouth 
to mouth Ixing eni[)loye(l at the s^'Ctions r— r. 

Concrete Tunnel Lininf^s.— No. 21,904/13. E. R. Callhrop. Accepted September 
2c^/i3. — -This invention jnovifles an improved method for lining tunnels and like 
excavations or borings with concr<te. The tn<thod consists in progressively building 
up sections of tubular form by means of shuttering having means whereby the shutters 
may be so connected togctther that they are mutually supported without the use of 
independent scaffoUling; two inverted cantilevers meeting at the crown of the tunnel are 

240 




Fif^s. 1—3. 
Concrete Tunnel Linings. 



(^vFSofNSSiS'^'] RECENT BRITISH PATENTS. 

formed to supiiort the concrete in j)()sition, ;iiul the latter is vibrated in situ to obtain 
a coni|)Iete tul)ular section in which the tensile and compressive stresses are equally 
(lisiril)ut(xl throughout \\li<-n tlu- concrete- is s<'t and tlu- laj^j^in^ r<'mov<d. 

("oncicle is laid over the bottom of the tunnel and as far uj) the sides a.s j)iacticable 
the concrete heini; mechanically vibrated 1)\ an\ appropriate apparatus to compact IIk- 
particles together, thus renderinj^ it waterlimht and |)r(\<nlin^ the suhsecjueni foiiiialion 
of hail' cracks oi' fissures. 

A middk' or " key " laj^i^inLj or sluitt<r (2) is arranged up(jn th<" concrete and is 
exactly Ci-ntr-ed, such as by a pkmib-bol). l'\n'ther l.'ij^j^in^s (<S) ar<' now placed uj)on 
ejich side of the " k<'y " (2) beinj^ t<'mporaril\ att^aclu-d thereto and to adjaci-nt la^j^inj^s 
bv sta\' rods (c)), lh<' laj^i^ini^s heinj^ c(>nn<'Ct<-(l to <-acii otlK-r h\ suitable UH'ans to prevent 
them shiftinj^. 

Each ia^i^inj^ is i)r(nid<'d at its <nds with brackets (10, Fig. 2) connected by a bar 
(11) to which are pivotally conm^cti'd the two stays or struts (9), th<' free <'nds of which 
are so form<d as to enj^a<:^e with the bar (11) of an adjacent la<^j4in^, and so rigidl\ 
connect the two to<^ether. 

The hii^iiinj^s bein<4 connecUd together, as, for instance, by the aforesaid hinjfes, up 
tt) the point where the walls begin to curve upwards and inwards, concrete is then filled 
in behind them and vibrated as before, and the building up of the section having thus 
been proceeded with, each successive lagging is connected as above described to the 
one preceding it and concrete placed upon it as indicated at 12 {Vig. 3). The lagging is 
then closed up on to the wall of the tunnel and secured in position, and this operation is 
repeated till the section is nearly complete. When nearing the roof or crown of the 
tunnel the roof is completed h\ filling in concrete from the end of the section after the 
lagging is in position. 

This is effected by providing light metal tubes of a length corresponding to the 
length of the section under construction and filling them with concrete. The tubes 
so filled are placed in the cavity and withdiawn against the action of plungers. The 
concrete will thus be left in the cavity, but in order to entirely fill the space, rods of 
matured concrete are then driven in until the filling is complete. 

In order to facilitate removal of the lagging when the concrete is set one or more of 
the laggings is made collapsible. 

Waterproofing Cement.— y.o. 5,908/13. G. T. Hill and C. G. .Stone. Accepted 
December 4 13. — The object of this invention is to strengthen Portland cement and 
render it waterproof. 

The invention consists in adding magnesium silicate, in the form of soapstone, 
steatite, etc. The improved product, when used in the usual manner with certain 
proportions of sand or silica and mixed or tempered with water, forms a mortar which 
after setting is waterproof, and possesses tensile strength from 40 to 100 per cent, higher 
than mortar made from ordinary Portland cement. 

The magnesium silicate, which may be added to the cement in the proportion of 
from I to 10 per cent, by weight in the form of a fine powder, must be thoroughly 
mixed in the cement. In order to ensure this thorough mixing, it will probably be found 
the most practical to add it during the process of grinding the cement clinker. 

The magnesium silicate can be fed into and ground in the mill together with the 
cement clinker, so that its proper incorporation with the cement and also its degree of 
fineness may be assured. 

The magnesium silicate may of course be ground to the necessarv degree of fineness 
by other means, and then mixed in the cement in the desired proportion bv hand or 
machine mixing. 



24.1 



H, KEMPTON DYSON. 



[CQNCKETE] 




PART II. 
By H. KEMPTON DYSON. 

The folloiving article has been ivriiten by the Author to further explain the question 
of loads on pillars, "which 'was touched upon by him in his articles which appeared in our 
journal last year on the London County Council Regulations on Reinforced Concrete, 
Part L of this article appeared in our March issue.— ED. 



It is frequently assumed that flat-ended struts are in the same condition as fixed- 
ended struts, but there may be a considerable difference. With flat ends no tensile stress 
can be developed at the ends, because these are merely kept in contact with the bearing 
surfaces by pressure. With fixed ends, on the other hand, such tensile resistance can 
be developed. With steel we do not need to employ different equations for the condition 
when the eccentricity is such as to develop tension on one side of a strut, as we do 
in connection with reinforced concrete, in which the concrete is not to be relied upon 
to act in tension; but even with steel we should note that when the eccentricity of the 
thrust departs from the core section of a fiat ended strut the condition of the ends 
quickly approaches the hinged-ended condition. Up to that point, however, flat ends 
are as ^ood as fixed ends, and in reinforced concrete, as this analysis only is true on the 
supposition that the eccentricity of thrust is never so much as to be likely to cause 
tension at any i)art of the section, we may regard flat ends as the same as fixed ends. 
In the case where the ends are neither flat between nor monolithic with j^arts of sufficient 
rigidity to maintain the axis at the end in the original position, the ends should not 
be looked upon as fixed. In f)ractice the ends of pillars are often not so held, the beams 
and slabs at their ends being too flexible, to give conijjlete fixity. In such a case of 
imperfect fixity W(; might take as an ai)i)roximation U as equal to //3. 

In order to distinguish how far we can go before we are likely to get tension on 
one side we should need to determine; the core section. In the case of solid rectangular 
sections of one material only this is a rhombus having the i)rincipal axes as diagonals, 
the corners being set along each axis at one-sixth of each diameter from the centre. 

Consequent 1\, if ^ exceeds - we \Mi(\ lo look into matters closely. This, in the case 
d U 



of round sections, becomes a limit of 

exactly by setting off ordinal es along 
the X axis, according to th(,' equation 

242 






The core section mav be found more 
the y axis, corr(!sponding to chosen values on 



1, trjN.vrkMK-noNAi; 



SLENDHR STRUTS. 



= _ ^" . -l^' - \- - ^ 



fiy- ym 



Xtn 



in wiruli i^ , .iiul i^y .lit' (lie i.ulii of {^M.ilioii .ihoiil llic axes of x aiul v rcsjx'c t ivciv, and 
x,„ and r,„ ;"i' tlic maxiinuin (-o-ordinalcs of the liniilinj^ points of zero stress- nanidv, 
tliosc points of the section situated farthest from the eentroid of the section. 

There is still another condition for /^. that requires to Ix- determined namdv, 
the strut havinj^ one end fixed and tlic other hini^ed hut k< pt in its orif^inai lateral 
position (see I'ii^. 5). 

To keep th(> hini^ed end in its position a lateral force /'" must he applied at the 
hiui^e, while at th(> fixed end there is a moment M. Then the moment at a jjoint 
distant x from () is — 

M, = Py~F(l-x) 

and the equation of the elastic curve is — 

El'^4 = F{I-x)-Py. 
ax' 

Integrating, we have — 

y=-A cos x\/-l,'-+B sin xV§-,+~{l-x) 
hi El P 

in which A and B are constants which can be determined bv the ' 

dv ' 

conditions that y = when x = and -^^ = when ,r = We find thereby / 

ax C 

P 



and 



B = -V^. 



P ' P 



Substituting these values, we get — 



3' = f(-/cosxV|-, + V'|^ sin;.\/|, + / 
P EI P EI 




X). Y^ 

Putting J = for AT = /, we get either F = 0, in which case there is no 



Fig. 5. 



bending, or 



tan Zv/ 



EI 



EI 



The angle in radians whose tangent is equal to the angle itself is 4*493 radians 
approximately. 

/\^r- = 4-493 



EI 



Therefore 
and 

Inserting the value for y in the equation for the elastic curve, we have — 



Fl 

P = 20T87^. 



dx 

Equating —4 to zero we get- 
dx' 



Elp= -Fl cos x\/f +F^EI_ ^.^ ^y^. 
dx EI ^ P ^ EI 



tan ^-^^ = 4-493 

the solution of which is a- = '30087/, which means that the point of inflexion is situated 
'30087/ from the fixed end and '69913/ from the pin end, and that the value of h for 
this condition is '34956/. 



2*3 



H. KEMPTON DYSON. 



iCgNCBETB 



In the London County Council's second regulations for reinforced concrete the 
value of the virtual lent^th v of a pillar in this condition is given as \/2l, the virtual 
length being that of a fixed ended pillar of equivalent strength. If this were true, the 

value of -v from the pin-end should be -^/=7071/, but as in that case x would have to 

equal '2929/ the foregoing equations would not be satisfied. The L.C.C. regulations 
ought therefore to give the value of v as 2 X '69913/= 1*4/. approximately. 
Collecting the foregoing, we have : — 



Condition of End<5. 



Value of /c- 



Both ends fixed 

Both ends imperfectly fixed 

One end fixed and one end hinged and restrained from lateral movement 
One end fixed and one end hinged and guided into a position where the 

lateral movement of the free end is half the total deflection 

Both ends hinged 

One end fixed and the other end neither hinged, guided, stayed, nor 

supported 



1/4 
say, / 3 
•34956Z 

1/3 

1/2 

I 



To determine all the constants in the formulae for struts we still require to 
ascertain two properties of sections— namely, g/d and n/d. For the four types of 
pillar reinforcement shown at the top of Fig. 6 the following analysis applies :— 

Let / = Inertia moment of area of concrete equal to that of the core of the 
pillar (as shaded in diagram) 
Is = Inertia moment of the steel sections. 
A ~ area of core. 
4 s =" area of steel sections. 
d = diameter of pillar. 
r = radius of any bar about centroid. 
Is = /, /. 
As = A,A. 
II A = N/i\ 

Av = area of one vertical bar. 

_ /4 



S = diameter of one round bar. 



'Av 



Iv = inertia moment of one vertical bar. 
It does not matter whether we refer dimensions to rectangular or diagonal axes, we 



get for Type 1 



, _As_A,A 
4 4 

TT 



A^' 
4 



2,r 



•cry 



For TyPG 2 — Av = 



U = A^r 

Aa_A,d' 






8 8 



27r 

2 






244 



('a. OON.STUUCnONAL 



SLENDER STRUTS 



1'\m- I'ype 3 



^"~6 24 



6 



For Type 4 — 



16 



&v 






Generally 



and 



Also 



I d' \ d'\ 
= -7- = t:^ X ^, = — for rectangular sections, 

/ ^d' -^ d\ . ^ 
-—:=y. X ,-. = 77 for circular sections. 

/ + (m-l) /s /[l + (m-l) /J 



and 



i Ar,[l + (m-l)/J 



Inserting the forci^oing values, we get : — 



For Type 1 — K. _ 

d' 



f2 + ("^- 



iM.[(-V^)%^;] 



\ + {m-\)A, 



For Type 2 



For Type 3 — 



For Type 4 



1 



d- 



l + (m-l)A, 



l + (m-l)^, 

The formulae for various values are plotted on the diagram {Fig. 6). The values 
of gjd and njd for homogeneous sections of various shapes are given in the table on 
page 45. 

The combination of the values of gjd, derived from Fig. 6, with the values of njd 
for the various shapes of the four types of reinforcement is performed diagrammatically 
in Fig. 7. 

We are now in a position to use Figs. 6, 7, and 3 to determine the resistance^ of 
slender struts of reinforced concrete. Fig. 3, of course, will serve for any material. 

245 



H. KEMPTON DYSON. 



ICDNCBETEi 



Figure. 



I = Moinent of Inertia 



^> = Radius of Gyration. 



iild = KM\o of Distance 

between neutral axis and 

extreme fibre to Depth. 




y , CTON.vrUUCTION A 
«i.IJS(klNKIrJ/lN( 



SAll 



SLENDHR STRUTS. 



I he iinincclialc |)ui|)()sc ol this .11 (iclc is to correct the \'.ilu(s lor {alculatin}^ the strength 
of struts put forward in the L. (".('. RcLjulations for Reinforced Concrete Buildings 
in London. 




Type 



k..^uM 



Only etched core 
areci taken. 
/^// bars assunned 
same s/zg. 




■ 



/\-area of concrete 
^g =■ ch sfee/ 
j4,=arec// ratio /^y^ 



Eo-=^ modulus of elasticity of concrete 
£^- do do. da steet 

/-- inertia moment of steel 



g= gyration radius 
d^dianneter of core 

(outside to outsida of longi- 
ti/dinals S wfthm bindirxf) 



Vblues a^ C,=(m-/)y^, 




Values oi C -(m-/)^, 



Fig. 6. 



[Copyright of H. Kemptun Dyson.] 



Let us take first the most adverse case, and see how the L.C.C. regulations 
compare with Alexander's and the Gordon-Rankine formula — namely, a pillar of type 2 

247 



H. KEMPTON DYSON. 



lOQNCRETD 



able to bend about its transverse axis, and reinforced with i per cent, of vertical steel 
bars, and constructed of concrete proportioned i cement, 2 sand, 4 coarse material, whose 
ultimate strength, as ascertained by tests on cubes cast in moulds and made with the 
material as used on the job, is not less than 2,000 lbs. /ins though the average strength 



n^disfanco fhom naufryjl axis to afctreme stfye. g^g^ynation radius. d=diair>etBf of cor-^. 



Values o( §§ 



^^^lll^lllkb[lfl^ll^l!-^ 




Values ^ ^ 



l"'i<;. 7. [Copyright of H. Kenit>ton Dyson.\ 

as realised on cubes cut out of the work would be over 2,400 lbs. /in-. This becomes 
further justified by considerations of eccentric loading in conjunction with variation 
in the modulus of elasticity of concrete as the stress increases. 

Then lie " 000 Uc = 1 ,440,000 and m = ^^^^9^= W>_00 _ 21. 

Uc 2,400 

Travelling from the vaku; 21 in the; left-hand margin of Vig. 6 until the line for 
value of A^, marked 'oi, is met, next vertically upwards to the conjunction of a 
horizontal trace from the intersection of the A ^ line marked "oi and the " C, index line 
for type 2," the fjarallcl to lli<- lines \()V values of (l^ C„ until we meet the " C\ index 
line for squar(;s," now outwards horizontally to meet the vertical trace from the 
very first intercejjt derived, we find ^^/<i — "49. The process is shown by the guiding 
arrow lines. 

Now, going to Fig. 7, we find the value of g/d = '^() in the bottom margin, travel 

248 






SLENDER STRUTS. 



vertically upw auls uiUil tln' line i^ met niaikcd " Sqiiart- on diagonal," next horizontally 
to ni(>('t the value of e/ii. an. I I hen verticall\ upwards to the top marginal scale, we 



deiixc the value of 



11 (• 



K ^ 



'The pioi-ess is ai^ain sjiown hy j^uidinj^ arrow lines. 



b'inally, i^oiui^ lo Fii^. \, we ohtain the following; values for a fairly lonj^ coliiinn of 
21) ft. in hei'-hl, which, because it is iniperfecliv li.xed, will have a value of l^ = 20x 12^3, 
so that c = -oi /^. -^ -oi X 20X i2-i-3=o-8 inch : — 

Vai.uks ok Qi'Ai ikikk Q I'oK Impi;kkectlv Fixed Knds. 



F^or a Slenderness Ratio of 

l/i = 
or l,.lg - 


12 

.8-2 


14 
9-5 


16 
10-9 


18 
12-2 


20 
13-6 


22 
15 


24 
16-3 


26 

17-7 


28 
19 


30 
20-4 


Value ofe/g =■ 


•1 


•1 


•1<.9 


•122 


•136 


•15 


•163 


•177 


•19 


•204 

• 


L.C.C. Regulations 

Rankine 

.Mexander ... 


•833 
•876 
•9 


•625 
•856 
•895 


•458 -375 
•84 1 -825 
•877' -86 


•292 
•81 

•842 


•25 
•7«.5 

•822 


"•208 
- -78 

•8 


•76 -75 j -74 
• 8 •7591 ^738 



It is necessary to explain that in the foregoing table the values given for the 
L.C.C. Regulations are derived from the actual ones therein contained by multiplying 
by •833, because the working stress in direct compression is 500 lbs. /in-, whereas the 
stress in beams is put at 600 lbs. /in-, the stress thus being reduced to | ='833 times 
the ordinary permissible stress. 

We see from this that on any basis the values in the Regulations are too extreme 
for exceptional cases. On the other hand, in struts w^hich are hinged at one or both 
ends, or are fixed at one end, and which are long though bulky and consequently not 
verv slender, the accidental eccentricity created in construction might be so great as 
to render the L.C.C. values unsafe. Therefore the author thinks it would be much 
better to give a table well on the safe side for pillars imperfectly fixed at both ends, so 
as to be simple enough for ordinary uses, but to permit engineers as an alternative to 
calculate the struts by a formula of the Alexander type with the particular constants 
aforesaid. 



2 19 



H. SCHUERCH. 



ICQNCKETFJ 




REINFORCED CONCRETE 

VIADUCT, LANGWIES, 

SWITZERLAND. 



By H. bCHUERCH, Chief Engineer of Messrs. Ed. Zueblin & Cie, Strassburg i. Alsace. 

The folloivina is a free TransluHon taken from an article ivhich appeared in our 
• contemporary, Armierter Beton," and -which lue publish by the courtesy of that 

journal. The illustrations ■were placed at our disposal bv Mr, Schuerch, and our translation 
has been prepared by Mr. C. Wesemann, Ciziil Engineer.— ED. 



The viaduct here described is being- constructed on the route of the new Chur- 
Arosa meter gauge electric railway, Switzerland, close to the villag^e of Langwies, 
and is necessary for carrying- the permanent way across the valley of Plessur 
and Sapuenerbach, where two streams come together on the site, and where 
when the snow melts these mountain brooks often carry down enormous 
quantities of water and pebbles, for which a free passage is desirable. 

The lack of suitable building- material and the difficulty of bring-ing- heavy 
steel work on to the site, owing to the bad condition of the roads, as Vv^eli as the 
existence of good gravel and sand material on the spot, led to the use of 
reinforced concrete for the construction of the viaduct. 

Objections were raised in the first instance by the Swiss Railway Depart- 
ment (to whom the designs had to be submitted for approval) to the use of 
reinforced concrete for a structure of such magnitude. Finally, however, the 
contracting firm, Messrs. Ed. Zueblin & Cie, of Strassburg, who had been 
at gr«'at pains in the preparation of the design, and had worked out the static 
calculations most carefully, succeeded in <jbtaining the necessary consent tO' the 
use <jf reinftjrced concrete, the tender being supported by ample guarantees. 

The bridge crosses the valley with one main arch of 96 m. clear span 
between the abutments, i.e., 100 in. span from centre to centre of the springers 
(h'ifj^. i). The theoreti(\'il rise between (X'ntre springer and centre crown of the 
;.rch is 42 m. (^n either side of the main arch are a series of four smaller open- 
ings, each ha\ing a clear span of i4"7 m. Beyond the end abutments three more 
openings were afterwards added, on the side towards Langwies, instead of an 
earth embankment, proposed in the first place. Two of these additional openings 
have a clear span of 13 m., and the remaining one has a clear span of 10 m. 
The nature of the subsoil admitted of the central section of the viaduct being 
construcl<'d in form of an elastic or non-hinged arch, whereas the dec^k of the 
outer spans was designed with continuous girders, as the great elevation of the 
roa-^lwav |>latform above groiiiid nccessilalcd a structure without horizontal 
thrust, the liigh and slender pillars being sufficiently elastic to admit of the 
dilatation of th<: railroad slab. In addition to this the latter is separated by 
means of expansion joints at the top of the siipj)orting double pillars. Owing 

2 ^o 



^ii, CON.STPIKTIONAI 
C\ KN(.INb-l-RlNti ^ 



RI£INF()RCHI) CONOR ETH VIADUCT. 



to its liij;!! aliiliulr (i,J-(^ 'ii- ;il><>\i' sc;i-l('\('l), the viadiuM is exposed lo j^reat 
('h;in«'i'S of ti'nij)ci ;iiiii I', .m<l tlirirl')rr tlu' (luislioii of cxij.'insioii :tiul coiil r;t(iion 
li;i(l lo 1k' (^irrrully l;ikcn into fonsidiTation. 

VUv c-cntial span (■onii)risL'S two st'i)aralt' afchcd rin^s, llu; 1lli(-kn(•s^ of 




251 



H. SCHUERCH. 



ICQNCBETEi 



which is 2-IO m. at ihc crown. The width of either rib at the top of the crown 
is TOO m., and, beini^" battered lengthwise, it increases reg-ularly from crown 
to spring-er. The two arched riiigs are tied together by means of rigid cross- 
Ix^ams. 

With tlie view of ensuring- greater stabiUty, the whole of the viaduct 
(including- the skeleton pillars) is battered upwards {Fig. 9). 

l"he road\\a\- is 4 m. wide between the parapets. This dim-ension Includes 
070 m. for either side-walk. The railroad consists of a 30 cm. ballast-bed, 
\\hich is underlaid by a layer of sand, resting upon the insulated cement floor of 
the railroad blab. The latter stretches between transverse g-irders, of which 




r\^. 2. \'iew of Arch Ceiureiiif4 in ICarly Stages of Construction. 

RkINKURCED CoNCRKIK VlADun. LaNCIWIKS, SWIT/KULANI). 



ihose at ihc lop of the j'illars ha\c a greater (le])lh in order to obtain an increased 
rigidil\' in liie transverse dirc;clion of tlie slal). 

The lonL' iuidiii.'il vi'-ders of the siii)erst ruet ure of the central arch are ron- 
tinuous i)eams running ihrouglioiit the foui- spans, and are connected at the 
cr.ywn uitli tiie arch itself and al)o\e liie si)ringe)-s with tlve al)utment pylons. As 
the connection with the erown ol the aich does not allow of any n-iovement, the 
pillars liad to be suflic iently elastic to allow lor the e\])ansi()n and contraction 
of loDgitucJiiial deck-gii'ders. 

Tlv' main girders of the outer spans are <'ons1ructed in the form of beams 
with a \arving moment ol iii'-rlia (I'lg. 7). 'Ihey also run (M)ntinuously over 
four :-j\a]is, and <ire <-onne<te(l with iheii' supports in such a manner that a 



2 c 2 



Tj, CXDN.vrkMR-nONATl 
L«VF.N(.1NH I^INt. —J 



RHINFORCED CONCRETE VIADUCT. 



c'c'rl;ii:i ainouiit of moxomi-iil is ])()ssil)li'. 'Vhv hcarinij" phitcs al the points of 
.sui)i)()rl ol llic i)ill;irs of llic :)uU'r s]);iiis h;i\i' Ijccn i educed to :i n.irrou ni.irj^in 




Fig 3 \'ievv of Arch Centreini^. showinti part cf finished Concrete Work. 




Fi.^. 4, Front \'iew of finished Arch Centremi; show ins Cabla Ropeway. 
Reinforced Concrete Viadlct, Langwies, Switzerland. 

of area, with the view of ensuring a hinge effect. Regarding the pillars them- 
selves, they are constructed in the form of skeleton pillars [Figs. 6 and 9), viz., 



I) 2 



253 



H. SCHUERCH. 



iCQNCBETE l 




W 

X 5 



two cross-tied uprights, 
as the wind forces are 
carried along the road- 
way slab direct to the 
^ respective abutments and 
to the huge double 
pylons on the other side. 
The latter, therefore, 
instead of being cross- 
tied by single transverse 
beams, are braced to- 
gether by means of a 
solid cross-spandrel wall 
{Fig. 6). The inner pair 
of uprights is connected 
with the roadway slab of 
the central span, the 
outer pair with the road- 
way slab of the approach 
openings, in order to 
allow either section of 
the viaduct to expand or 
contract independently. 

The construction of 
the viaduct has been 
designed from the point 
of view of ensuiing a 
maximum saving of 
material and a minimum 
as regards actual 
stresses. This was ren- 
dered more p o s s i b 1 <: 
owing to the live load 
on the bridge being a 
comparatively light one 
in proportion to its dead 
weight. I'his also ex- 
j)lains the application of 
two cross-tied arched 
ribs instead of a mono- 
lithic ring, although tlic 
latter form has also 
l)een carefully tai<cp into 
(M)nsi(leration. 'i'he static 
calculation of tlie viadu(i 
has b e e n l)a s e d on 
the assumption of a 



251 



fj, cr>N>"n,>MtTic»N(AT| 



r1':lvf()rch:d concrete viaduct. 



ti'st-load train ihal comiM-iscs iwo loconiolivi'S of O5 Ions scrvirc ueij^lu each 
(tin- 1\|)o ol tin- ivliailic Railways), and an unlimited number of adjoininj,^ j^oods 
trucks thai are e()ui)led in one direc lion. Willi rej^ard to the static calculation 
of the se(H)n(larv ^iiders — viz., the railroad (U'ck and the minor spans — an 
addition lo the ahoxx- lixc load of 1;; \wy eenl. has been considered. 'I he addi- 
tional forces 
thai ha\e been 
lakeii into ac- 
c o u n 1 com- 
prise : — 
(i) \ tempera- 
ture change 

of ± 15 
deg. (Cel- 
sius) ; 

(2) Contraction 
due to sett- 
i n g- — 20 
deg. 

(3) Braking 
force s — 
one-seventh 
of the total 
weig^ht o f 
the loading 
train-axles. 

(4) \\ ind pres- 
sure : 

(a) lookg/m-, 
when the 
bridge is in 
superloaded 
condition ; 
[h) i5okg/m», 
when the 
bridge is in 
unloaded 
condiiion. 
The modulus 
o f elasticity- 
has been as- 
sumed : 
E = 2,000,000 t/m-. 

E steel 




The proportion 

E concrete 

The safe maximal compressive stress of concrete 



25 



H. SCHUERCH. 



iCQNCB ETE! 



providing- the dead weight of the bridge is combined Avith the most 
unfa\ourable superload (Hve load); 

o-=45 kg/cm, 
prcviding all the secondary and additional forces are taken into account, 
i.e., temperature, contracting- due to setting, braking-forces and wind- 
piessure. 

The safe shearing stress of concrete is assumed : 

T=4 kg/cm-'. 
Safe tensile stress of steel for reinforcement : 
= I, GOO kg/ cm-, 
provided the dead weight of the bridge is combined with the most unfavour- 
able superload (live load) ; 

cr= 1,200 kg/cm-. 




Finished Beams and Centreinj^ to OpenintJs on the Lanjiwies Side. 
Keinforckd Concrete Viaduct, Langwies, Switzerland. 

provided all the secondary and additional forces are taken into account. 

The ab<)\e figures are based upon the assumption that the concrete (that is 
mixed (^n the spot and is daily controlled and tested by a Martens' set registering- 
apparatus) shows thi- following minimum standard strength after 28 days of 
setting-time : 

180 kg/cm-, 

when being rammed on the spot in a jjlastic condition (poured concrete); 

250 kg/(>m-% 

when being ranmicd on the spot in a moist condition. 

Th-' Rittcr method was cmployctd in ihc caltmlations of the internal stresses 
m all those parls of the const ru<iion that ai-e siibjecM to cM)mpression — I'/.G., 
the cenlr.d ar( li .ind tlic pillars and also loi- the determination of the tensile 
bending stress ol tl)c conf rclc (onst riK I ion, whereas the Christophe method 
was adopted in (alculaling the inleinal stresses o/f all the other ])arts of the 
structure— namely, those j)arls thai are subject to bending forces and foi- the 
calculation of the reinforcemeul . The shearing forces were \erv carefully deter- 
mined, and s!eel rods in ! lie lorm ol stin-u])s are j)|-o\ ided \\here\er they extx'cd 
the safe shearing stress ol concrete- -7;/£;. : 

256 T = 4 kg/cm^. 



&: 



t:N(JT^t-lJ/lN(i — 



REINFORCED CONCRETE VIADUCT. 



'Vhv ii-sislaiuc at^iiinsl (■(>lhi|)sini4 was talciihilid accordiii"^ lo llic Killir mclliod. 
The piu'iiliar art li-cciU rciii;^ (/'"/i,'.v. 2, \ and .]) is well woilli special incniion. 
'I he uppi'i -pait ol the falsework has hccn const riiclcd in the lorm ol a fan iaiill nj) 
wilh re und linilKT ohlainahlc on live spot in i^reat lcn«4lhs, at a low jjricc and ol 
^ood «;|ualit\. This tiinhiT si-alToldinL; is sup|)orlc'd l)\' three reinlorced concrete 
towers whiih ha\c ])i'en constructed in the form ol Iraniewoik or skeleton 
towers. The reason for these reinforc^i'd concrete lowers was due to the 
followiui^' causis. It was not. ad\ isahle to obstruct the \alley loo much by the 
falsework, as the sea ff oh linj;- is exj)()se(l to dani^cr (rom Hoods, an<l is thus 
liable to damai^e at times when the snow melts and tin- two mountain brooks, 
which j(,>in just on the buildiui^ site, carry d(^\\ n enormous masses of water and 
pebbles. For this v ery reason the erection of a scalToldinj^ comjjosed of uj)riy;hts 




Fig. 8. Reinforced Concrete Towers in course of construction. 
Reinforced Concrete Viaduct, Langwies, Switzerland. 

was out of the question, and the tower system only was suitable {Fig. 8). Timber- 
work towers would have obstructed the passage more than reinforced concrete 
towers, and furthermore they would not have possessed the same amount of 
stability. The substructure and the foundations would in any case have required 
the use of reinforced concrete exen if timber-work towers had been erected, 
as the driving- of wooden piles was absolutely impossible on account of the 
nature of the subsoil, which is composed of coarse pebbles and is intermixed 
with loose blocks. 

The total settlement of the main arch had to be reduced to a minimum, and 
this also was another reason for using reinforced concrete for these towers. 
When the central arch was closed the arch centreing- showed a total settlement 
of, roughly, 30 mm., inclusive of 10 mm. which occurred through the head- 
pieces of the diagonal struts cutting into the capping-pieces of the stringers. 

^57 



H. SCHUERCH. 



ICQNCKETEI 



The erection of the viaduct was beg-un late in 1912, but at the commence- 
ment of the work operations had to be confined to foundations of fhe abutments, 

winter setting in be- 
fore time and causing- 
an interruption of the 
work for several 
months. Not before 
April, 1913, could the 
work be resumed. Bad 
weather during- the 
early summer delayed 
progress once more, 
and especially pro- 
tracted the completion 
of the falsework of the 
central arch. Later on, 
however, the weather 
chang-ed for the better, 
and by the combined 
efforts of all those con- 
cerned in the work, it 
was finally rendered 
possible to complete the 
arch-centreing for the 
most part on Septem- 
ber 6th and the con- 
crete work of the larg-e 
arch — excepting for the 
closing- of some joints 
— on October 6th In 
1913. The last of those 
joints, which were kept 
open intentionally for a 
long time, was closed 
on October 27th. 

The winter, of 
course, has ag-ain inlcrrupKd th-- work. Init Mill, the approach openings on ihe 
SKle toward Langwies are now completed (Fz/,r. ^j ; so is the main arch and the 
whole of the p.llr.rs of th(^ superstructure above the central section [sec Froniis- 
piccc). llu: pill.-irs ol lh(- outer spans on the side toward Arosa are partlv 
finished. TlM-n- n n,;,,ns In be . r„nph-tc(l this spring the roadway platform above 
the central span and above tin; appro.,, h op.nnigs on the side toward Arosa. 

The buIMing of thi.. viadun has called forth a series of rather ample 
mvcstigations and tests as to the strength of concrete, steel and timber, 
mcluding- tests on the elastic j)ropcrti(s ol concrete. 




liti. 'J 



■r(:jtioi), and side 



Side \iew of Aicl) CeniicinK m coijisc 
openiiifjs toward Lanswies. 

RkINF JRCED CoNf.KKTK VlADUCT, LaNGWIKS. SwiTZKRI.ANI). 



258 



r^i-"S,'>ri^V^Ji"S^ CA!.CULATI()NS FOR STEEL-FRAME BUILDINGS. 




■ CALCULATIONS AND 
DETAILS FOR STEEL- 
FRAME BUILDINGS 
FROM THE DRAUGHTS 
MAN^S STANDPOINT. 

ByW CYRIL COCKING. M.C.I. 

In xiieiv of the importance and great 'value of this Paper, ivhich ivas read before the 
Concrete Institute, ive are qi'vinq an abstract of same as a principal article rather than 
under our heading "Recent Vieivs." There ivere numerous tables at the end of the 
Paper ivhich are of remarkable excellence, and ivhich ivere referred to in the discussion but 
ivhich ive have not been able to reproduce here. Only a short resume of the discussion is 
also given. The Institute is to be congratulated upon this Paper. — ED. 



The draui^htsman's point of view in the methods of calculation and preparation of 
details for mod<'rn steel-frame ])uildin^s is a most im])ortant one and is seldom con- 
sidered. 

In order to L>ive the draui,^hlsman a fair start it is necessary that certain matters 
should be agreed upon between the architect or his deputy and the district surveyor 
before the architect's plans are sent out for competitive tenders from constructional 
firms. 

The district surveyor should be consulted at the very commencement of every job 
regarding which he may have any discretionary powers. The matters to be so discussed 
and agreed are chiefly the following :— 

PARTICULARS OF LOADING, ETC., TO BE AGREED WITH THE 

DISTRICT SURVEYOR. 

1. Dead and Superloads. — All firms competing should be provided by the architect 
with the fullest possible details and particulars of floor construction, roof coverings, 
ceilings, casings to beams and pillars, partitions, the proportion of masonry in external 
walls — such as heavy cornices and ashlar work — and all special loading, such as lift 
gearing, water-tanks, heavy safes, travelling cranes or runways, etc. 

2. Foundations. — The maximum pressures allowed upon the soil ; the fullest possible 
Information should be given for the design of party-wall foundations; depths and 
extreme limit of spread for foundations to j^arty-wall pillars. 

3. Eccentric Loading. — The District Survevor's requirements for the treatment of 
eccentric loading on pillars. 

4. Pillar End Fixing. — The District .Surveyor's decisions as to what shall constitute 
a fixed or hinged end for the purposes of preparing the pillar calculations. 

5. Form of CaJcidations. — The form in which the District .Surveyor requires the 
•calculations and detailed drawings to be prepared for submission to him for his approval. 

Provided the above information is given to all the competing firms the competition 
would be a fair one, and it is open to engineering firms to combine together and insist 
upon the receipt of such information before agreeing to tender. 

Other considerations which should be impressed upon architects in general when 
agreeing to tender are, firstly, that the engineer should be allowed a reasonable time 
in which to prepare his scheme and tender ; and secondly that, should he be successful 
in securing the contract, he should have at least two to four weeks' start in advance 

259 



THE CONCRETE INSTITUTE. [CQNCBETE] 



of the builder or ij;eneral contracted- in order to ])repare his working drawin^^s and 
settle the exact positions of the pillars, foundations, etc., and the fabrication of the 
steelwork required for the first deliveries. 

In the past it was the practice to consider the loadin<f on a floor as inclusive — 
that is, the loadper square foot upon which the calculations were based was assumed 
to include the weii^ht of construction; now, however, it is becoming the practice to 
ascertain individually the superloads, dead weights of floors, beams, pillars, beam and 
pillar-casings, etc. This is certainly a distinct improvement, and tends towards greater 
accuracy and economy in design. 

SUBJECTS FOR DISCUSSION. 

Eccentric Loading. — What is the effect of eccentric loading? This interesting 
and important question is not so easily ansv^ered as one would suppose from a casual 
consideration. 

Take the case of a pillar composed of a lo in. x 5 in. I at 30 lb. and 2-8 in. x | in. 
plates, and which is considered as possessing one end fixed and the other end hinged^ 
and is capable of supporting a central load of 53*4 tons on a laterally unsupported 
length of II ft., according to the stresses allowed by the Act. 

Assuming that the stresses allowed by the Act bear a factor of safety of 4, the 
central load causing failure would be equal to 213*6 tons. 

Xow let us consider the load of 19*95 tons aj)plied to the web of pillar as being 
an eccentric load, the connection being made with a well-stiffened seating rivetted to 
the web of the pillar. The seating or bracket being stiffened, the load would 
undoubtedly be considered by the eccentricity devotee as acting on the extreme edge 
of the seating angle. 

Assume that this angle for the case under consideration as being an 
8 in.X4 in. X I in. angle. 

The eccentric arm would therefore be 4 in.+o"i8 in., equals 4*18 in. 

Now the eccentricity coefficient from the formula usually adopted, i.e.r 

Cc = 1 + .,, is equal to — 

4:iA>i4^6-46, 
175- 

therefore the additional equivalent central load to that already included on the Pillar 

Sheet is ef^ual to — 

19'95(6'46-r25) = 103"9 tons, 

giving a total equivalent central load of — 

103'9 + 48"4^=152"3 tons, 

thr- maxiiiuiin fibr<- s-tr<-ss being — 

also the factor of safct\ being — 



152 3 ^iQ.28 tons/in.-'. 
14-82 

213-6 



1-4. 

152*3 

I<"urtlvr, tin- actu.al stresses induced in ihe ])illar will dejiend to a large extent 
upon llif 'Icptli ;uid (l<tl((tion of the Iw-.-ini, the width and monunt of inertia of the 
pillar, and the rigidit\- of the (onnection of llu- beams to the i)illar, also chiefly upon 
the continuitv of the pillar at the U\*\ of ihc beam connections — factors which the 
befor<'-m<-ntioned formula coiispic uoiisl\ ignores. 

As soon as \v<- make ihe pillar conlinuous or securcl\' fix the I'lids lh<' stresses are 
entirelv altered in their distribution, and the efhcls of {])<■ <((<ntri(ity vary from one 
to one-half those com[)Uted by ttie usual formula according lo th<' amount of continuity 
and fixture ;it \]v ends. 

260 



r-TT^STPMCTioNAi.] CALCULAriONS FOR STEEL-FRAME BUILDINGS. 

■V\u' ciiH'siinii ni,i\ !>.■ (onsi.l. 1. (1 very siinplv in ihc f()ll()\vin«^ mannrr : 'I'akc, for 
<'x;iinpU-, .1 i)ill;ir supporiiii- .i ( .intil.\<T in the ni:inii«T shown in I'i^. i. In its 
(1('11(hM((1' fnrni such ;i i)ill.ii wuiKI inihciti' ,m reversal of he ndint^ moment at the ron- 
iKH-tion of ihr oantilrv. T to the piliai , the Io\v<r pillar curvin-^ out to th<' left and the 
upiHi- pillar i-urvini4 out to th.' li-ht .U'arlv indicalinii that tlw stresses du<- to 
(^M-entricitv ar<- distrihut<d both ahov- and Ix'low the point of connection, and not 
below onlv as i*( mrallv assumed. The sum of the eccentric stresses in A and li is 

approximatelv equal to W-^, and ih.' sum of the total sti-<-sses C and I) is equal to 

\\(i~\\ 'Vhc i)illar heini^ continuous the stross<"S would he dislrihuted half abov<^ 

\ii ^ • • , 

and half helow the connection, th(r<'fore the total eccenlric str<'ss m A in tension and 

in H in comi)ression would In- <qual to ^, and similarly the stresses in (' in com- 
pression and in 1) in tension would he equal to ^(^-ij, or th<" total stresses, and 

similarlv the maximum stresses jx r square inch, are about one-half those comj)Uted m 
the usual wa\' b\ tlie formul.a — 



W 
A 



2/>^' 



-J 



(CCMBt-j) 



Ann of Eccentricity. —S^ome engineers hold the opinion that the eccentric load on 
a pillar acts at the centre of area of the seatinjf throui^h which the load is transmitted— 
that is, at i)oint A on Fig. 2. Aoain, others contend that the eccentric load can be 

assumed as acting in the plane of 
the external face of the seating— 
that is, at point B on Fig. 2. 
Yet again other engineers assume 
that the eccentric load acts in the 
plane of connection of the seating 
to the pillar, point C on Fig. 2. 

End Fixing of Pillars. — 
Another difficult point regarding 
which the draughtsman must 
exercise his knowledge and expe- 
rience is the question of " end 
fixing " to pillars. What con- 
stitutes a fixed end? What can 
be termed a hinged end? Also 
what relation does a flat end bear 
to either or both of the above? 



Ct«mVi) 




I: A 



Fig. I. 



Fig. 2. 



The opinion is generally held that the topmost connection of a pillar in the topmost, 
storey and the lower connection of a pillar in the bottom storey shall be considered as 
hinged ends, though the latter connection or base of the pillar could reasonably be 
considered as a " flat " end. 

Also it sieems reasonable to assume that the pillars in external walls which only 
receive two- or three-wav connections shall be considered as having one end hinged and 
the other fixed. 

The important question remains, When can a pillar be assumed to possess both' 
ends fixed? 

Where a pillar is continuous both above and below the connection at two con- 
secutive floors, and receives at both floor connections or " ends " a four-way connection. 

261 



THE CONCRETE INSTITUTE. [CONCRETE ] 

In which the heavier or deeper beams are conn-ected to the pillar perpendicular to its 
weaker axis, such a pillar shall be considered as having both ends fixed. 

These three important questions — -eccentric loading, eccentric arm, and the end 

-fixing of pillars — should seriousl}- be considered by the Institute, and the District 

Surveyors' Association should be approached with the object of arriving at practical 

solutions of these problems. 

■X- * * * ^ 

After a most valuable chapter on Calculations, which it is impossible to deal with 
in summary owing to the references to the illustrations and diagrams, most of which are 
omitted, the author went on to deal with the following questions : — ■ 

Deflection. — The question of deflection is not one that need cause us any grave 
concern, for Section 22, Clause 7 of the Act clearly indicates that the question of 
deflection can be ignored, excq^t in cases where the ratio of span to depth of beam 
is greater than 24. When this ratio is exceeded the calculation of the deflection must 
be made in order to ensure that the maximum deflection shaill not exceed j^^yth part 
•t)f the span. 

When it is requir< d to use shallow beams the flange stress must be reduced in 
order not to exceed the permissible deflection. 

For plate girders, comjjound girders, and lattice girders in which the modulus 
of the cross-section is proportioned to the bending moment at various points along 
the span, the depth being constant, we may consider such beams as beams of uniform 
strength for the purposes of calculating the deflection. 

Seeing that the greatest deflection for a beam of uniform section is obtained with 
a uniformly distributed load, it is quite suflicient for all practical purposes to treat 
a beam which has to support a complex system of loading as if it were loaded with 
the equivalent uniformly distriouted load. 

Shear.- — The maximum vertical shearing values for webs can be ascertained from 
the following formula- — 

where .s = maximum vertical shearing value for web in tons, 
f = thickness of web in inches, 
c/ = total depth of web or I beam in inches, 

']'h<- dejith of an unstirf<'ned web must not exceed sixty times the thickness of web. 
This is a very liberal ratio, and should be reduced somewhat for very thin webs. 

The question of rivets acting in double shear is one that is apt sometimes to be 
overlooked, especially when designing pillars and beams where w^eb connections are 
made on both sides of the beam. The bearing values for the rivets through the webs 
of pillars and beams should always be inquired into, especially when using the lighter 
sections, such as 10 in.x5 in. I at 30 lb. and 12 in.x5 ^"- ^ ^*t 32 lb., which have 
relativ<'ly thin webs. 

Floor loists enclosed in Concrete. — It is generally admitted that steel beams as 
lillers or floor joists i-ncased in concr<-te provide a much stronger floor, strength for 
•strength, than if the (oncrfle were omitted. Therefore it is onh reasoaable to make 
some alicjwance for !lii> addil ioiial sirenglh in design. Al the same time it is iK'cessary 
to bear in mind llie restrictions as to slrt-ss and the proportion of depth to si)an 
r<'quir^fi by llie Ael. Tlv additional strength can Ik; calculated b\- tin- usually acoe|)ted 
f(jrniiila for conipiiiiiig the slrengtli of reinforced concrete l^eams. 

In (jrder to ]<(■<■]> within the hiiiits of span to (1( ptli prrscrilx'd l)\' the Act, we are 
'justified in assuming that the depth of the heain is from the (o|) of concnte assimied 
as acting with the beam lo the underside of I beam. 

After s(jnie inieresiing remarks regarding the tpiestion of rivet pilch, grillage bases, 
Tnansard work and wind pressure, the author concluded with the following remarks: — 

262 



i 



, lON.M k>U("T10NAL 
tN(ilNbtJ^lN<i::-l 



CALCULATIONS I^^OR STEHLFRAMB BUILDINGS. 



CONCLUSION. 

I would ur_Li<' tli;it .ill runvlriicM lon.ii ciiLiinccrs ;in<l (Ir.iiiLlhNmcn should su])|)ort llic 
London I>uildin_i4 Acts i()0() Anit iidnu nl , ;ind ih.it the Concn'lf InstiiuN' should do ;dl 
that is in its powxT to fosl<r ihc iMtUr sj)irii of lo-ojnTation for h.irnionious wcjikin^ 
bi-lwccn I hi- ^-nj^inccr who has \o dvsii^n and erect sliy-l-franK- huildinj^'s and tin- district 
surveyor who is appoint<'d to s(<' that th<' rccjuirt nunls of the Act ar<' faithfully obscrvt^d 
and conij)rK'd with. 

II nia\ be ihoui^ht by some that c<Ttain anicndnicnts to tlu- Act would be d<-sirabl(', 
init in this connection no concessions can be oxix'ctcd. or obtained unless all concerned', 
w ith th<' workini* of the Act combin<' toi^cthcr to make the very best of it as it is in its 
present condition. 

As an Act it is both fair and })ractical, and time has already shown that it has 
been the means of considerably inijjrovinj^ the j^eneral desij^n of steelwork both from 
the standpoints of £^ood practice, economx, and theoretical design. 

FoUoivhio upon the paper iJurc uuis an iiiicrcsiiug discussion, of 7i'/n"r// we here 
f^ive a sliort ueeoujit : — 

DISCUSSION. 

Professor Henry Adams, M.Inst .(' .E., who was unable to be present, wrote saying lie 
echoed the author's hope that all constructional steelwork might be carried out in accordance 
with the London County Council Regulations, whether legally subject to them or not ; also- 
that the steel-frame work should be directly under the control of an engineer, while the 
architect contnied himself to the architectural features. He did not understand the author's 
relief at not being required to make allowance for the eccentric loading of beams. All 
competent draughtsmen had always been in the habit of making this allowance, and also both 
to provide for the structural load and the superimposed load. He did not agree with his. 
statement as to what the eccentricity devotee would take for leverage distance on the pillar. 
With regard to the question of submitting calculations to the District Surveyor to enable him 
to judge of the sufficiency of the design, he agreed if his duty merely consisted of checking 
the arithmetical accuracy of the calculations, but if his desire, as he assumed it to be, was only 
to determine the efficiency of the design he should say, judging from his own experience- 
in practical w'ork, that the calculations were a hindrance rather than a help, as he found that 
the shorter w^ay was to make his ow^n calculations on the basis of the loads to be carried. 
Many of the author's approximations were very useful, but he did not agree that the depth of 
an unstiffened web might reach sixty times the thickness. He certainly never adopted so- 
extreme a ratio. The author's tables of safe loads on standard beams massed in concrete 
would be found very useful. He had not seen any published tables of this kind before, 
though this method of construction had been largely adopted for the last fifteen oi twenty 
years. 

Mr. F. E. Wentworth Sheilds, M.Insi.C.E., thought that the interesting Paper fully 
justified the action that the Council and the members had taken, in doing their best to en- 
courage Papers other than those on concrete and reinforced concrete. It showed how very 
closely allied the different branches of structural engineering were ; indeed, that it was almost, 
impossible to have a broad and comprehensive view of materials like concrete and reinforced 
concrete without some study of steelwork design also, and that the study of one was immensely 
advantageous to the study of the other. He agreed that the tables given at the end of the 
Paper, in which safe loads for British standard beams encased in concrete were given, were 
most useful and interesting. A little while ago he had occasion to consider a case of a floor 
which consisted largely of British standard beams encased in concrete, and he found that 
although the concrete casing added very considerably to the strength of the steel beam, it 
was almost impossible to take advantage of that fact because there was such a very high 
friction stress produced by the loading between the flange of the girder and the concrete. In 
this particular case the load was unusually high: ten cwts. to the square foot. He did not 
gather whether the author had gone into the question of friction stress between the steel and 
the concrete in making up these tables. This was a most important matter, because the 
concrete casing round a steel beam would only increase the strength of the steel beam provided 
that the steel and the concrete worked together, that was provided the beam did not slip- 
within the concrete. If the beam slipped, then presumably the concrete casing w-as of little- 
or no advantage to it. 

263 



THE CONCRETE INSTITUTE. ICQNCBET EI 

Mr. IF. G. Perkins (District Surveyor for Holborn) thought the author was distinctly 
wrong in stating that one was not required by the Act to make any allowance for the eccentric 
loading upon beams. What the true eccentric loading was it was difficult to say, but in the 
pamphlet published by the District Surveyors there was a formula given for taking into 
account the eccentric loading upon pillars, which might be taken as accurate for ordinary 
practical purjwses. If the connections were made perfectly, the beams fitted tightly up 
against the pillars, and the pillars were continuous, then perhaps the bending moment might 
be reduced by 50 per cent., but as the Act allowed pillars being placed upon pillars they did 
not get that perfect continuity in the pillars, nor did they get the perfectly fitting joints, and 
in that case he thought the formula of the District Surveyors was the proper one to use. It 
was not theoretically correct, but they said in the pamphlet, as the buildings should be 
sufficiently braced that there should be no material deflection in the pillars the formula had 
been adopted in preference to the more complicated one necessary in cases where material 
deflection occurred. He should be very glad that the Institute should have a conference with 
the District Surveyors. As they generally had to work with architects, he itiought at the 
same time they should invite the Royal Institute to send their representatives to such a con- 
ference. As Secretary to the Science Committee he would endeavour to do his best to bring 
about such a conference. The grillage was not really the foundation, the griuage was the 
base of the pillar ; the foundation was defined in the byelaw as being the concrete, and if they 
regarded the concrete as the foundation and the pillar bore directly upon a series of grillage- 
beams, which were properly stifi"ened and so arranged that the bearing loaa did -not exceed 
that allowed by the Building Act, they could then take the grillage as the base of the pillar, 
and they would not be bound by the regulation which governed the rivets in the gusset plates. 
Referring to wind-pressure, he remarked that the general public were not acquainted with the 
failures that took place in and around London. As an old official it had been his lot to see 
several buildings which had been blown over in the neighbourhood of London by wind. 

Mr. S. Bylander observed that if the Institute would adopt the recommendation of the 
author, that a Committee should consider the further regulations which might be required in 
order to make the Act for steel-frame buildings smoo-th working, he thought it would be 
welcomed by all concerned. Complicated and troublesome work they wished to* avoid ; they 
wished to simplify everything. If they knew exactly what to do they would work with 
greater pleasure. He would suggest that they should extend this still further, and that the 
Committee should recommend to the London County Council that they should supplement or 
amend the present Act as far as might be desirable. The author seemed to mix up the engineer 
and the contractor. His (Mr. Bylander's) idea was that the contractor would save a great 
deal of expense if particulars were provided by the engineer, and he was sure that the con- 
tractor would never be able tO' expect very definite and reasonable information and require- 
ments unless it had been prepared by an engineer thoroughly conversant with the particular 
work. It had been proved to be successful that the quantity surveyor took out the quantities 
from one scheme prepared, and these were afterwards submitted to the contractors for tenders. 
On the question of eccentric loading for pillars, he for one thoroughly believed in the assump- 
tion that the load was applied on the centre of the beam and not on the face of the pillar. 
The assumj^tion that the load was applied at tlie outer edge of the angle was thoroughly 
wrong. If there was a stifTener underneath it was most likely the load was applied uniformly 
over the bracket. He suggested that the allowable stress for pillars should include, say, 
20 per cent, of the eccentric loading. This would simplify the calculations very considerably. 
His contention was that it did not matter a bit whether there were beams on four or two sides; 
the main thing was that the connection between beams, whether two or four, was sufficiently 
-Strong to hold the column lateral. He did not believe in the stiffening efl"ect of the beam to 
the pillar by means of connections in order to keep the column rigid. As to beams buried in 
concrete, he thoroughly agreed that it was the adhesicm between the steel beam and the concrete 
that they had to watch ; that was an extremely difficult thing. He did not believe in the 
method of steel beams buried in concrete being the same as reinforced concrete. It was a 
most dangerous assumption, ills alternative, which lie thought would meet the case, was a 
much simpler one. A beam in solid f:oncrete ttvuld carry a much greater load than a beam 
not supiKjrted in that manner. If the beam was endK'dded in cone rid' the floor would be 
three feet on either side. TIk 11 the>' should be able to allow a nnii h higher stress. He 
further suggested that the stress of beams embedded in floors should be increased by, say, 
20 or 25 per cent, 'i'liis would give a fair allowance for (he fact that the beam could carry a 
heavier loarl if \\<)\ laterally supported. His belief was that before they got any considerable 
stress in the concrete they had reached the excessive stress in the bottom flange, and, therefore, 
they might at once dismiss the cahadalions of the top flange, and only consider the bottom 
flange. 

264 



^GiiSSI^j CALCULATIONS FOR STH EL-FRAME BUILDINGS. 



N(.lMt-I RlNCi^ — J 

]\lr. E'iVarl S. Atuirt'ws, />..S\. (/.<>//</.), said there had iilways seemed to liiin :i tremendous 
ainoiinl of misunderstandinu; on tlie- i):irl of en|,dneers as to the failure of lualliemat iciaus to 
produre suitable formula' for lluiu. 1 1 is own opinion was that dire(tly jjraeticul engineers 
sIiowimI uiathemat i( iauN that tlic\ rcallv were interested iu ^;rtliuff a formula which was 
accurate llu- luathcuiat i( ians would rise to tlu- occasion and ^'ive them that. 'J"hc whole trouble 
was that there seemiMl to hv a dtMuand for halfd)aked formula-, whii h did not satisfv the 
mathematician at all, and whi( h looked sulliciently simple to satisfy the engineer. Tliey 
seemetl lo be met b\ this call for simpli(it\', which he was sure was a ver\ bad thing. It 
was imi)ossible lo rcdme c(uuplicate<I formula- into simplicity. He liad given (onsiderable 
thought to the (piestion of etii-ntrii loading, and he was cjuite in agreement with the main 
idea of .Mr. Cocking's result. As to halving the ec( entricitx', though, lie did not understand 
the mode b\- whi(h he had attained it. 'J'he only wa\" they would ever learn the actual 
stresses in the cohnnn was by actually measuring tb.em, and the work that was being done in 
America at the i)resent time in that direction was work that they ought to watch with very 
great care. 



26s 



C. \V. BOYNTON & ]. H. LIBBERTON. 



ICDNCKETEJ 




Sample of Panelled Ceiling Work done with 
Sand or Plaster Moulds. 



THE DECORATIVE 
POSSIBILITIES 
OF CONCRETE. 

By 

C. W. BOYNTON and 

J. H. LIBBERTON. 



O- 



=o- 



the 
(Vol, 



We give below an abstract of an interesting Paper luhich was read some time ago before 
Western Society of Engineers, U,S.A,, and reprinted in that Society's Journal 
No. 8, 1913). Ttie Paper was presented by Messrs. C, W. Boynton and 



J. H. Libberton, to "whom lue are indebted for our illustrations. The Paper comprised 
numerous other illustrations and examples which are notgi-ven in this abstract. — ED. 



There is an old maxim to the effect that the desig-ner should ornament his 
construction and not construct his ornamentation. This is an admirable saying-, 
but should be subordinated to another rule, that he should ornament his 
structure only if he lacked the skill to make it beautiful in itself. A structure 
of anv kind that is intended to serve a useful end should have the beauty of 
appropriateness for the purpose it is to serve. 

There is a certain charm about a massive structure almost irrespective of 
design. The sight of a p\ramid on the desk would call forth no expression of 
interest or enthusiasm, but let this grow in size until it assumes the proportions 
of those famous structures of Egypt and many pilgrimages will be made to 
\ i':v\ it. Of course the I{g-yptian pyramids are assumed to be the resting place 
of kings, and the placing of the l)]()cks required the use of more muscle or 
nia<liiner\ than we at present ha\'e an\' knowledge of, but our idea of their 
Ixiauty and grandeur obtains ])rimarily from the immensity of the structures. 

There is no reason, however, why mass should not be combined with 
decoration, j)ro\'ided the design is not made subordinate to the decoration. 
This combination has often been used very effectively. The question is, what 
medium shall be chosen? At the Unity Churc^h, Oak l^irk (F/.:,'. i), the 
building is not only monolithic concrete, but the ornamentation partakes of the 
same characteristics, havii^g Ix'cn (^ast at tiie same time and of the same 
material. In <i building of this 1n|H", however, nnu^h attempt at dei^oiation 
would he fatal, and the unobtrusive style adopted detracts not in the slightest 
from the dig-nit\- oi)Iain!(i by large areas and inassixe construction. With a 
different style of buildijig, ■ u( ii as llu- Administration i^uilding at Washington 
Park {Fi^i;. 2j, the treatm<nt ni.iv ix' entirely different and the (M)ncrete be 
called on to assume the most intricate shajjes. 

266 







•- CON^vryiKHIONAL 
Ci. EN(.lNhb.WlNt. — , 



DECORATIVE POSSI EI LIT! ES OE CONCRETE. 



liolh of lluM- huildiiii^s show tlx- same siirfnci- finish. Tlic :ir(hitc<iurL' 
(Klrnn lus tlu' (Irc-oration. W'ilh coiKhtions reserved and the dcioralions Irans- 
l)osi(l liu' elTecM would l)e hidicrous. In huildini^ the monotony of llie form 
eonerele has lu'en relieNcd h\ the use of a rathiT (hv surface mixture w liicli 





Fig. 1. Detail of Unity Church, Oak Park, Illinois. 
The Decorative Possibilities of Concrete. 



discloses the nature of the ag"gregate used. In work of this kind particular 
attention must be paid to methods of obtaining uniformity of surface and 
absence of horizontal joint markings, although the latter blemish is not nearly 
so noticeable on work of this character as with the wet mixture. 

E 267 



C. W. BOYNTON & J. H. LIBBERTON. 



LCONCBETEJ 



But the question of pleasing effects depends not only on the surfaces and 
the surface treatment, but on ^ the combination of design with the surface 
texture. When not carried to extremes, the judicious use of a few division 
marks relieves the plainness of design and forms a rather interesting frame- 
work for what would otherwise be a monotonous surface. 




l-'m. 2. JCiitraiice Detail, Administr.itioii liuiMiii;^, W.isliinjiton Park, Cliica^o. 

TlIK IJKf;f)KATIVK PoSSIHII-ITIKS OV CONCRKTK. 



!)(•( cration howcx'cr, is not an essential of mass (-onslrutiion, as has been 
clearly dcmonsl rated bv the Sj);inish in tlie design of tlie a(l()l)e dwellings and 
missions. Hut adobe perishes and our interesting relics of former days will 
soon be a thing of the past. Noting the i)()ssil)ililies of monolithic^ eoncretc for 

268 



n 



OON>TI.M ICT1CBM4U 



!)HC()RATI\'Ii POSSIBILITIES OF CONCRETE. 



j)r( St rxiiii^- this arcliiu-cluif, Mi', l-'iaiik Miller, I'.S.A., has uiKk'i'lakcii Id 
j)L'trir\ iiuk'linili'ly, as it wiTi-, soinr ol llu- inosl iiiltTcslin^ details of the 




Fifi. 3. Courtvard, Glenwood Inn, Riverside, Cal. 




Fig. 4. Glenwood Inn, Riverside, Cal., looking from the street into the Courtyard. 
The Decorative Possibilities of Concrete. 

mission architecture developed by the Franciscan Fathers in California {Fig. 3). 
Thus when the last adobe wall has crumbled we still shall have a replica of the 

E 2 269 



C. W. BOYNTON & J. H. LIBBERTON. 



ICDNCRETB 



Campr.nile of San Gabriel (r /i,'. 4) and the imposing arches of San P'ernando, 
these having- been duplicated in the Glenwood Inn at Riverside, California. 
Little other material than concrete has been employed — except the roof tile, 
which undoubtedly lend colour to the scheme and interest to the picture. On 
the roof is a famous collection of bells, over 300, dating^ back to 1278. 

Of a mission tvpe, also, are the rest or way stations of the Pacific Electric 
Railwav, at Pasadena, California. These are fast replacing the old wooden 
rouo-h and readv stations, none of which was consistent with the high class 




Fif* 5. Porch Detail of a Residence in Soiitli Oranj^e, N.J. 
The Decora iivE Possibilities of Concrete. 



residential district thrcjugh which the company operated. On both sides a 
bench is built into the wall so as always to furnish protection from rain. 

Because it inrludcs some ol the most notable sculpture on the coast, the 
building of tbc 'I'lirfjop Polytechnic Institute at Los Angeles, Cal., may have 
interest. Jl is all of reinforced concrete. J he sc^ulpture was executed in New 
York and cast in glue moulds by a local (M)mpan\'. Warm climates seem par- 
ticularlv suited to j:lain concrete construction, and its general adoption may 
partially be explain'-d by tlic cool appearajice of the plain surface. 

Concrete, still in its lormali\c stale of de\ clopment , is a comparatively 
/lew architectural material, although structurally it has been proving^ its 
perma.nen<:e for man\' \ears. i Ik- particular reason for gratification comes in 

270 



'y, fON> IPlKTlONAi: 
' A t:.N( il N KKk 1 N( I ^ — ; 



DECORATIVE POSSIBILITIES OF CONCRETE. 



tlu' new (liM«)\ crii s, Ami new uses lo which il is cont iiui;ill\ hciiiiL; put. I^xfry 
cl;i\ sonH't hiiii^ new a\\(\ worlhx ol coiisidci;!! ion is (hscoxcrcd. 

Mi-. 1' ri'dciiik Si|iiii(S, ol Xcu N'oik City, h.id xit'Ucd uilli rcj^rcl the 
j)r(.Sfnt slab ;ind hf ini lloor const lucl ion. Alti-r scvi'r.il \c;irs ol studv, he 
d(,\iscd ;i mctliod ol (hi|)lieat iiijL; the most intricate ol cast ceihn<;'.s in .solid 
in)ncrc-te, with a decided sa\inLi ol material. Ills scheme eonsists simj^lv in 
eir.jilox iiii^ lawerse colfeis of moulder's sand, whi<h are j)laeed on the lorm 
l)e!v)i"e the concrete is p;)ui'ed. When the forms are remoxed, the panels are 
exposed, the whole heinij' accomplished in one ()|)eration. Tar more pleasing 
surfaees are ol)taini'd than wt-re excr piesenled by the old ])laster-of-paris 
mcth,)d of ap|)lyini^- j)re\ii)usly east ])anels lo the work. 




Fig. 6 Porch Detail of a Reinforced Concrete Residence at Woodbury Falls, N.Y. 
The Decoxative Possibilities of Concrete. 



A few years ago the theory of applying concrete by means of a hose and 
nozzle met with derision, but every day we hear of more work being done by 
this method, the machine being designated as the " cement gun " and *^he 
concrete "gunite." An interesting piece of work has been accomplished by 
the Boston Ele\ated Railroad at the foot of O Street, Boston, where a garden 
i^encc has been constructed bx this method. The base and posts are built of 
concrete poured into the forms in the usual way, the posts being relieved by 
protecting brick quoins. The street face of the panels were shaped by means 
of a xxooden form, and each central panel xvas faced \xith steel. The concrete 
xvas applied from the rear with the cement gun, making the panels 2^ in. thick 
and the styles 4 in. thick. The interesting point in the operation is that the 
entire panels are made in one piece and at one operation. 

The ver\- fact that concrete is simple in operation has caused many to 

271 



C. U^ BUYNTON & J. H. LIBBERTON. 



ICO^CBETFJ 



undertake construction who are in no way fitted to carry it out, but with proper 
super\ision even the most unskilled labourer can accomplish pleasing- results. 

A building- should be fitted to the country in which it is to be located, and 
more and more attention is continually being given to the unity which must 
exist between the landscape and the layout of concrete structures which are to be 
added as permanent improvements. 

An interesting example of concrete for houses is seen in the detail {Fig. 5), 
the residence of Mr. Albert Moyer, U.S.A. Liberal use has been made of 
exposed aggregates, employing a mixture of Portland cement with limestone 
screenings, marble chips, and dark trap rock. Not stopping here, much 




I'ijl. 7. Interior View of a Reinforced Concrete Residence, showinfj substitution of Fresco for Lattice Work. 

The Decokative Possihilitiks ok Concrete. 



dependence has been j)lace(! upon Moravian j^otlery decoration, which har- 
monises well with the concrete surface, 'ihe balcony, also, has been worked 
out in pottery. I lie dislinguisliing feature lies in the fact that instead ol 
being inlaid, the figure comes out in Ijas-relief, and although somewhat serpen- 
tine in design, seems fairly consistent with the grape-vine moti\e. 

l<"or some time Mr. Alfred llopkins, of New V'ork City, has been a strong 
advocate of reinffjiccd concrete lor the fonst ruction ol buildings, and has 
added a large amount ol inlorniation I0 our knowledge ol the coiKM'ete ol the 
old Romans, leaving in\ estigalcd liiis |)oint jxTsonally and in some detail. 
Nevertheless, he has nexcr brought himself to beliex'e that concrete should be 



272 







aTcoNsfvurndNAL. 

(^ KNC.INKFWlNd --; 



DECORATIVE POSSllUEl'l lES OE CONCRETE. 



usi'd !()!• tlu' orn.iiiii nl.ilioii upon 'Duildini^s ol tlu- s.iinc in;iUii;i!. I'()r this 
ini'-posc lu' a(I\()(MU's tciia cotl.i. lie Ikis recently erected :i larj^c r<-sidence at 
\\'(>()dl)ur\ h'alls, ^.^ . This hiiihliiiLi is all ol reiiiloiced concrete to the rool, 
and part i)l" this has hi'i-n const ructid ol concrete slabs. lUit for the panels 
and column c.ipitals teira colta tile has Iveen used. i^'or the average individual, 
of course, a detail of this kind would hi' i)i()hil)iti\ t- in cost. Hut with such a 
sized undertakini^- as this nianiinolh lesidence, the hi^h indixidual cost of these 
panels is small when comi)ared with the total cost of tlu' building. However, 
whh the adxances which are being made in the use of coloured aggregates, it 
is generalh j)ossi1)le to obtain all the colour variations necessary in the concrete 
itself. 




tiieplace Detail, Economy Concrete Co., New Haven, Conn. 
The Decorative Possibilities of Conxrete. 



It is not customary to build reinforced concrete roofs of the pitch type. 
In fact, there is no sensible reason for adhering to this construction when 
designing reinforced concrete. The ideal concrete house is built with a flat roof, 
n'jt only because architecturally the design may be made pleasing, but because 
this t\pe is the most economical in cost and space. An attic is of little use 
except for the storage of material which, in the majority of instances, will never 
be needed again, and when stored away in an attic corner invites spontaneous 
combustion. Reinforced concrete has brought with It a new architecture, and 
the sooner we appreciate its value the earlier will be the general adoption of 



C. \V. BOYNTON & J. H. LIBBERTON. [S3NCBETEJ 

reinforced concrete for residences as well as the endless other types of construc- 
tion to which it has already been applied. 

Lattice work has been utilised on important dwellings in combination with 
decoration of moulded concrete, and where some would use terra cotta, as in 
the panel inserts, others ha\e used concrete, depending- upon exposed aggregate 
to furnish the touch of colour needed. The lattice idea can be shown by simply 
stenciling the lines upon the wall, instead of using wood. (See Fig. 7.) 

Wood panelling will also break up larg-e areas of concrete surface, and is 
entirely in keeping- with the old half-timbered style of architecture, so familiar 
to ( ur forefathers. 

Stucco finish has found favour when applied to concrete blocks as a back- 
ing-, and there are some architects who believe that this is the only satisfactory 
means of handling- what has seemed to be in many cases a sad makeshift so 
far as a building- material having architectural merit is concerned. This im- 
pression has probably grown from the continued manufacture of rock-faced 
and inferior blocks by those who are entirely unqualified to undertake this kind 
of work. 

It has been stated the so-called dry process concrete block is not of concrete 
at all. Having- had little acquaintance with water during- its process of manu- 
fr.cture, it consequently harbours an unquenchable thirst, and when used in 
the outside walls of a building proceeds to make up for lost time, every rain- 
storm furnishing- the elements of a " spree " to the detriment of the block and 
the appearance of the dwelling. The dry process, however, is not necessary, it 
being equally as easy to add enough water to insure excellent concrete. The 
possibility of careful inspection during- its manufacture is a strong point in 
fa\-our i){ the continued use of this really excellent building material. 

'ihe Economy Concrete Company of Newhaven, Conn., have begun to 
demonstrate the possibilities of concrete for furnishing the ornamentation for 
buildings oi other material. The fireplace here illustrated (Fig. 8) is composed 
principally of (^namental concrete stone. The figures above the mantel are 
moulded after the various workmen about the plant, with the exception of the 
oni'. at the far right, who represents transportation. The other figures repre- 
sent in their order (\) the draftsman laying- out the plan, (2) the sculptor working'- 
o\'er ihc pattern, (3) the labourer pouring the concrete, and (4) the workman 
putting the finishing touches on the sur[a(~(' and correcMing any flaws caused by 
removing the forms. 

The vvf)rk is all cast in solid and uniformly j)roporli()ned ccjncrete without 
special surfacing, using wooden or plaster moulds. Where necessary glue 
moulds are employed for tin undcr-cu! w()r]<. This, of course, gi\'es a rather 
smooth surface, aiul is the on]\- criiicisin which could be made (jf the j)roduct. 
With t)ut slight additional (expense, however, the sui-face can be chiselled so 
a.-> to relie\'e what sometimes appeals to be a rather ])utty-likc surface when 
fresh from the uMiulds. 

Il should make no dillerence whether the stone trimming is artificial or 
natural, the end achiexed is tlial upon which wr should j)ass judgment. In 
reality, il matters not wiiether the aggregate in the concrele has been bonded 
by nature, or by the hand of man with Portland cement as the binding material. 

274 



y, CTON.vrUUtTIONAU 
A L,N(UNLtJ^lNti ^J 



DRCORATIVH POSSllil/JTIHS OF CONCRHTH. 



So far as |)('rinaiu'iuH' i^ concciiu'd, concri'ti- has alicadx proxi-d l)('\()iul a 
(l()ul)t its supiTioiity to many ol the natural sloiics. 

T\v'. writrrs, not hcin^; an-hitcrls, ha\<' dealt somewhat si)arin»4ly wiih 
the subject ol" ai (■liit«(-t ural and decoralixt' possibilities ol concrete, and lia\e 




Fig. 9. Reinforced Concrete Fire Station at Weston, Mass. 
The Decorative Possibilities of Concrete. 



rather depended upon the illustrations to indicate the purpose of this paper. 
After all, architecture and architectural decoration is a peculiar study. On 
the one hand there are those who contend for close adherence to the ancient 
styles of architecture, and on the other hand we have many brilliant minds 

275 



C. W, BOYXTON & J. H. LIBBERTON, ICQNCKETE] 

who have acliicxed wonderful resuUs and designed some of our most pretentious 
structures aloui;- entirely new Hues, yet without voluminous criticism from 
those w ho consider them.sehes authorities. However, since this paper has dealt 
more particularl}- with the architectural side of concrete, it is, perhaps, fitting- 
to close with a quotation from Mr. Oswald Hering", U.S.A., who has made a 
study of concrete and its architectural and decorative possibilities : 

" Concrete can be easily and rapidly manipulated. It is less expensive 
than either clothed steel or masonry construction alone ; it does not deteriorate 
with time, and it is practically fire and waterproof. It grows in strength for a 
considerable length of time, and after having attained its ultimate strength it 
never weakens, consequently by its use lighter, cheaper, and more durable 
structures mav Ijc erected than with any other known materials." 

Regarding concrete stone he says : 

"The time would seem to be not far distant when • concrete will very 
largely supplant marble and stone \Ahere castings are practical. These should 
not be 'termed ' imitations ' of stone, for the ingredients are largely the same 
as are found in real stone. Nature's process of employing time and gravity 
has sin-.ply been superseded and accelerated by man's mechanical ingenuity." 



27''^ 



y, CONM PUC-l lONAi: 
«v l.NdlNll l/INd ^ 



COSTRACTION AND EXPANSION. 




iimMm:rmmir\MmMmM\m\\\mm^ 



RECENT VIEWS ON 
CONCRETE AND REIN. 



L FORCED CONCRETE. 




RECENT PAPERS & DISCUSSIONS. 



It is our intenfion to publish the Papers and Discussions presented before Technical 
Societies on matters relating to Concrete and Reinforced Concrete in a concise form, ana 
in such a manner as to be easily available for reference purposes. 

The method toe are adopting, of di'viding the subjects into sections, is, ive belie've, a 
ne'W departure. — ED. 



THE NATIONAL CONFERENCE ON CONCRETE ROAD 
CONSTRUCTION, U.SA- 

CONTRACTION AND EXPANSION OF CONCRETE 

ROADS. 

By Messrs. R. J. WIG, N. H. TUNNICLIFF, and W. A. McINTYRE. 

An imporiaui Conicrcncc on Concrete Road Construction was held in Chicago m 
February, and nu)}ictous interesting Papers iverc read. One of the most important 
reports presented, says the " Engineering Xews," luas that of the Coniniittee on 
Contraction and Expansion of Concrete Roads. The Chairman of this Committee was 
Mr. R. /. Wig, of the Bureau of Standards. Tic give below a short abstract of this 
report and also of one on Aggregates for Concrete Roads. 

The data presented by this Committee show that the main cause of contraction and 
expansion of a concrete road, or for that matter of any concrete exposed to the weather, 
is not changes in temperature but changes in moisture conditions. While there has 
been more or less discussion of this subject by cement experts, it will come as a new 
idea to most engineers that concrete swells and shrinks every time it is wet and dried, 
just like a piece of timber, though of course not to the same degree. But it is established 
that the swelling and shrinking of concrete with changes in moisture is far greater than 
its expansion and contraction with changes in temperature. The Bureau of Standards 
has made most careful measurements on the experimental concrete road near New 
Village, X.J., and has found that the maximum expansion of the concrete in this road 
occurs in April when the road is thoroughly soaked by the winter's rain and snow and 
when the temperature has somewhat increased above that of the winter. The road 
then begins to shrink, notwithstanding the increasing temperature of summer, and is 
shortest in August when it becomes most thoroughlv dried out. 

One important lesson from this discovery is the importance of a rich impervious 
mixture for concrete road work, so as to make the percentage of water absorption and 
consequent expansion as small as possible. 

Another very important result of this Committee's work is its recommendation 
that the sub-grade of the road on which the concrete is laid be slightly dished instead of 
made flat or crowning. This tends to prevent longitudinal cracking of the road, as 
gi ivity tends to cause the two longitudinal halves of the road to slide toward the centre, 
thus inducing compression in the road. Further, with the sub-grade dished and the 
concrete surface crowned, the concrete will be much thicker in the centre than at the 
sides, giving it greater strength to resist longitudinal cracking. 

2/7 



CONCRETE ROAD CONSTRUCTION. [CQNCBET E] 



AGGREGATES FOR CONCRETE ROADS. 

By Messrs. SANFORD E. THOMPSON, A. N. TALBOT, and W. M. KENNEY. 

The successful devel()j)ment of the concrete pavement dejiends ii{)on : (i) Materials, 
and (2) Workmanship. 

It is not so much a question as to whether concrete is a suitable material for roads 
in comparison with other j3avin<4' materials, as it is a comparison between concrete and 
concrete. The durability depends upon the character of the concrete. 

Examination of letters received by the Chairman of this Committee from a large 
number of cities having concrete roads shows general satisfaction with this tvpe of 
pavement. Adverse criticism usually comes from cities where the specifications and 
description of work indicate either poor materials and incorrect proportions or improper 
methods of construction. 

AGGREGATE ESSENTIALS. 

Simple rules covering the most essential requirements are as follows : — 

(i) For fine aggregate, use only sand or other fine aggregate that has been actualh' 

tested for mechanical analysis and tensile strength of mortar, and is free from fine 

particles. 

(2) Use coarse-grained sands or hard stone screenings with dust removed. 

(3) Use sand or other fine aggregate that is absolutely clean. 

(4) For coarse aggregate, use hard stone, such as granite, trap, gravel, or hard 
limestone. 

(5) If bank gravel or crushed stone is used, always separate the sand or screenings 
and re-mix in the proper proportions. 

If local conditions prevent following any one of these rules, adopt some other 
material than concrete for your pavement. 

Hrieflx taking uj) each one of these j)oints : 

(1) Actual laboratory tests are necessary for fine aggregates, because it is impossible 
for the most expert builder to always distinguish by appearance between good and 
poor sands. .Sand may be coarse, of good colour, well graded, and apparently perfectly 
clean, and vet because of a minute quantitv of vegetable matter may show practically 
no strength when made into mortar or concrete. Case after case has been found where 
good-looking sand had to be rejected on laboratory test or, if used, produced defective 
concrete. 

(2) Coarse sand is necessary not only for strength and density, but to prevent the 
formation, on or near the surface, of a layer of fine material, consisting of a mixture 
of dust and cement which has no durability. Mortar made with fine sand or sand having 
a large {proportion of fine grains of silt, hardens slowly and is especially objectionable 
in cold weather. This prevents it attaining jjroper strength before the road is thrown 
open to traffic. A sand having a considerable proportion of fine particles may possibly 
show high briquette tests, and yet the mortar not have good resistance to attrition 
or wear. 

(3) Sand must be absoluteh free from vegetable or organic matter, or it is liable 
to harden not at all or too slowK to be serviceable. Frequently, sand may be entirely 
satisfactors' in appearance, and yet be worthless for concrete. Defective sand of this 
tvpe is apt to be taken from too neai" the surface of the ground, so that it contains a 
very small pericntage of vegetable loam. Al least 2 ft. of top soil and loam should be 
removed befor<- UNing the sand, and in mam cases it is necessar\' to take off as much 
as 4 or 5 ft., while occasionalh no acce|)tal)le sand can be found in the entii'e bank 
because of the peneti-;it ion to a great depth of the deleterious vegetable material. 

(4) A coarse aggregate of hard qualitv is necessary to resist the wear and abrasion 
of hoofs and wheels. h'ailures of concrete roads have been caused simply b\' the 
softness of the coarse aggregate. In one instance, for example, shells wer(> used lor the 
aggregate, and the ro.ad went to pieces as soon as it was subjected to wear. 

;\ll stone, like shale, slale, shells and soft limestone, must be rejected; while trap, 
granite and congUnnerale, aic specialh suitable materirds. A hard limestone, such as 
that occurring in certain localiliis along the Hudson River, which is sold in New York 
as trap rock, is satisfactor\' for concrete loads. A hard limestone cannot be cut with a 
k'nife and the specific gra\it\ is high, say, oxer 2"7o. 

278 



Q 



>,cr-N.vrut)c-rioNAU AGC^REGATHS FOR CONCRETE ROADS. 



(iravcl il(U's iiol bond t]uiU' so slroni^ly with ccniciil as docs broUcii stone. When 
propt-rlv scrcciiccl aiui fric from ilirt, however, and remixed with sand in the |>ro|)(r 
proportions, a _i;ood Mirface eaii he made e\<ii for a one-course i)avement. 

(5) Manx roads that are now heinj; hiiiU will |)ro\'e worthless because of the use of 
sand taken liirecllx from the bank without scrt-eninj;. If ihe j^ravel contains as much as 
40 per cent, of stones and very ricii proportions are used, say i pari cement to ^i P'Uts 
bank iiravel, a fair concrete can sometimes be produced, but it is always cheaper in such 
cases to screen the i^raxcl and remix the sand and stone in j)ro])er projjortions. There 
will be, for exampii-, a savinj^ of 4 bbl., or 1 bat^, of cenu nt jxr cub. yd. of concrete by 
usini;' projxMtions 1 part cement to 2 parts sand to 3 parts screened j^ravc-l, instead of 
usini^ the unscreened bank gravel in i)roi;ortions i : vi- '• ^""'^ di(Terenc<- will more than 
j)av for the additional cost of screenini^ the sand and rejectinj^ part of it. At the same 
time, the result will be more uniform and the surface more durable because^ of the stones 
which take the wear. When an access of sand is used in the mixture, as is the case 
with run-of-lhi'-bank j^ravel, the mortar rises to the top when the concrete is i)laced 
and the wearinj^ surface is less resistant than a mix that is uniform throuj^houl. 

If the rules i^iven above are followed, and at the same time proj)er foundations, 
proportions, and workmanship, are obtained, the concrete pavement will prove durable 
and will resist ordinary traffic. 

Tentative specifications for ai^j^rci^ates are present(d as follows : — 

FINE AGGREGATES. 

Oualiiy. — Fine a<4i^rei^ate shall consist of sand or screeninj^s from hard, durable 
i<ravel granite, traj), or other hard rock. It shall be clean, coarse, hard, free from dust, 
loam, vei^etable, or other deleterious matter. Fine aggregate containing frost or lumps 
of frozen materials shall not be used. 

Satuplcs for Test. — Average samples of line aggregate weighing not less than 10 lb. 
shall be taken from the bank or pile and tested, before the acceptance of the material, 
for fineness and for tensile strength in mortar. Individual average samples shall be 
taken from each bank to be used, and new samples taken in case of a change in the 
character of any one bank. 

Receptacles for shipment to laboratory shall be such as to retain the natural moisture 
in the sand. 

Fineness. — The size of the fine aggregate shall be such that the grains pass when 
drv a screen having |-in. openings. In the field a |-in. mesh or, in some cases, a ^-in. 
mesh screen may be used for this separation. 

Not more than 10 per cent, of the grains below the 5-in. size shall pass a sieve 
having 50 meshes to the linear inch, and not more than 2 per cent, shall pass a screen 
having 100 meshes to the linear inch. 

Tensile Strength of Mortar. — Mortars comjjosed of one part Portland cement and 
three parts fine aggregate, by weight, when made into briquettes shall show a tensile 
strength at least equal to the strength of i : 3 mortar of the same consistency, made at 
the same time, and with the same cement and standard Ottawa sand. The sand shall 
not be dried before being made into briquettes, since this sometimes improves its quality, 
but correction shall be made for moisture when weighing the materials. 

Tensile tests may be made at ages of 72 hours, 7 days, and 28 days. At earlv 
periods the strength need not attain the full ratio of 100 per cent, to standard sand 
mortar, provided this is attained at a later period. In no case, however, shall sand be 
accepted for pavement work whose strength in 1:3 mortar at the age of 72 hours is 
not at least 80 per cent, of the strength of the standard sand mortar. 

Screening.- — If bank gravel or crushed stone is used it must be screened and 
remixed in the proper proportions. 

If the sand does not fulfil the above requirements for fineness, it shall be washed, 
or else screened when dry over a lo-mesh screen placed at such an angle as to remove 
the particles finer than a No. 50 sieve. 

Washing. — Fine particles may be removed by washing with a large volume of 
water in a box provided in the bottom with perforated pipes and arranged for the silt 
and water to flow off through a trough from the top of the box and the sand to be 
drawn out from below. 

279 



CONCRETE ROAD CONSTRUCTION. [CONCKETE] 



COARSE AGGREGATE. 

Oiialiiy. — The coarse ao'ij;rei>ale sliall consist of clean, hard, durable granite, trap, 
congTomerate, gravel, or other hard rock, free from dust, loam, vegetable or other 
deleterious matter. In no case shall coarse aggregate be used which contains frost or 
lumps of frozen material. 

Coarse aggregate containing soft particles shall be rejected. 

Coarse aggregate shall not contain a large proportion of flat or elongated particles. 

Fincfiess. — P'or one-course pavements, the size of the coarse aggregate shall be such 
as to pass an inclined or rotary screen having i^-in. circular openings and be retained on 
a similar screen having |-in. openings. 

For two-course pavements, the size of the coarse aggregate for the bottom course 
shall be such as to pass an inclined or rotary screen leaving 2-in. openings and be retained 
on a similar screen having |-in. openings. 

For the wearing course in a two-course pavement, the coarse aggregate shall be of 
a size that will pass an inclined or rotary screen having f-in. circular openings and be 
retained on a similar screen having ^-in. openings. 

NATURAL MIXED AGGREGATES. 

Natural mixed aggregates shall not be used as they come from the bank or crusher, 
but shall be screened and remixed in the proper proportions. 



ASSOCIATION OF ENGINEERS-IN-CHARGE. 

THE STORAGE OF COAL. 

With Some Applications of Reinforced Concrete* 
By HENRY ADAMS, M.Inst.C.E. 

The folloii'ing is a short ahstraci of a Paper read before ihe Association of Engineers- 
in-Charge, on March nth, 1914. TJie lecturer illustrated the Paper by niiiuerous 
lantern-slides, and quoted luaiiy exaiiiples of the application of concrete for coal storage, 
a nu))iber of which have from time to time been given in our Journal. 

The author having been professionally concerned with the buiklings, machinery, 
and vessels used in the seaborne and inland coal trade for more than half a century, it 
occurred to him that it might be interesting to put together a few notes on the storage 
of coal in the course of its transmission from the ship to the consumer. 

Where open land is available the simplest arrangement for storing a large quantity, 
such as a whole cargo of 2,000 tons or more, at one time, is to jirepare the ground by 
levelling and then paving it with creosote d fir blocks, or with ranmied chalk. The latter 
makes a cheap and suitable bottom for a large storage ground as at Messrs. Wm. Cory 
and Sfm's X'icloria Dock Dejjot. 

I'he space can be divided into bins for different qiialilies or \arieties of coal by 
fences on three sides, composed of old railway sleei)ers let into the ground vertically for 
a foot or so, with old rails for longitudes, and oM crane chains to form lies to i)revent 
overthrow by pressure 

The coal is lifted from the shij)'s hold in buckets containing 15 to 20 cwt. and trans- 
ferred into small iron trucks rim b\ hand along an overhead gangway or limber viaduct 
to reach the store and ihen tipped, temjjorary rails of irj-in. square iron, attached to 
7-in. bv 2-in. fir sleepers, being laid along the heaj) as it i)rogresses. Or, in other cases, 
the crane is s(j |>la( ed ilial it can lift from the shij) or barge and deposit at once on the 
stacking ground, but in thai case it is generall\' a long-rake electric crane or a steam 
crane travelling along a jxrmanent viaduct as at Dowell's Wharf. The most rec<'nt 
arrangement is to have long radius cranes with self-acting grabs holding 15 to 25 cwt. 
to reduce the manual labour to a njiniinuni. 

Th(; storage of coal is ( hielU' required b\ the merchant who sells to the dealers and 
to privatf; consumers, and b\ the large corporations for their own us(^ in the production 
of light and power. 

The coal hoppers used b\ the meichants aie built almost entii'eh' ol timbei' on a 
])rick or iron column foundation, while those used l)\' the corj)orations ai'e mostly of 
brick. 

280 



I, CONMUM)C"riONAl. 



THE STORAGh: OF COM. 



I lu 11' is al\\;i\s a risk of s|)oiilaii('()Us I'Dinhuslioii where a larj^e tjuaiility of coal 
is stored, hut althoui^h the author has known of one or two cases, (here is not nuicli 
daiii^ei' where it is kepi inuiei eo\(i. In llu' \arious seahoine coal depots there is always 
sullicieiit nioveineiil j^oinj; ^n\ l)\ coal .L;oin_;^, out and other coal coniinj^ in to niininii.-,e 
the ri-.k. S|)onlanet)Us cond)iistion of iari^e colleclions of coal is more likely to hap])en 
when the carj^o has heen standiiij^ in trucks e\|)osed for some time to rainlall, so thai 
the coal is more or less damj) throughout, hut the suhjecl i^ somewhat oh^cur<-, and is 
well worthy of a sjx'iial Paper. 

I he question of the \\('at hei ini.*; of coa.! is of some im])o!lance. It has been est i!)- 
li^lud hexond doubt that coal exjjoxd to the weather deteriorates and loses some of its 
calorir.c \alue. The Admiraltv made some experiments upon storinj^ coal under watt r, 
ami i! was allciii'd at the time that it kept better than when exposed to the air, but 
po>sibl\ that result was desired rather than |)ro\(<l. It is often ik C( s>ar\ to store coal 
lor some considerable period in order to take ad\anta_<4e of cheap markets, and also to 
a\oid stop|)ai4es of work due to strikes in the coal trade; luuh-r these circumslaiic-s 
stackini^ to a heii^ht of al)oul O ft. upon the ij;i'ound is usually I'e-orled to, and it i^ 
likch" tliat a cover of tar|)aulins would hv of adxantaj^e. 

The present century has, however, seen the introduction of a new m(xle of buildiui^ 
which is peculiarly suitable for the construction of coal stores: reference is made, of 
course, to reinforced concrete. In this material, comjjosed as it is of steel rods embedded 
in concrete, there is the maximum of durabilitx and the minimum cost of maintenance. 
Structures of creosote d timber may last for lifty years, with increasinj^' expenditure for 
re|)airs after the first fifteen or twenty \ cars ; but in fifty years a reinforced concrete 
structure will be in better condition than in the year it was built. It is probable 
that in the future this will be the only method of construction adopted for the purjjose. 
It seems impossible to conceive of any better material; it has every advantage and no 
drawback. 

A somewhat fanciful objcciion to the use of reinforced concrete is bein<^ put forward 
by certain of the opponents to the employment of this material for structural purposes — 
namely, that, in consequence of its monolithic chru'acter a.nu its extreme hardness, th? 
work of demolition, where such is needed, ent;nls excessive costs. There is no doubt 
that the strength and toughness of buildings in r(>inforced concrete increase with age, 
and that in comparison with brick walling or even ashlar stonework, the expense of 
removal of the concrete is great, but the imperishable character of the structure and the 
small cost of upkeep are really great points in its favour. It is onl\- in rare cases that 
new buildings have to be removed shortly after being built. 

As an example of coal storage on a large scale, it ma\' be mentiont d that in connec- 
tion with the cable way from the port of Savona to San Giuseppe are twentv-four 
rectangular storage bins for coal, each of joo tons capaxitv, at Savona, and fortv-eight 
cubic bins measuring 5 metres each way, and having a capacity of 100 tons each, at 
San Giuseppe, 

At the Flossmiihle paper mills on the Continent a coal silo, 87 ft. 3 in. bv q ft. 6 in., 
with a capacity of ij,i26 cub. ft. in five cells, was constructed in reinforced concrete 
immediately over the boilers, with a tower at one end in which the hoisting apparatus 
was fixed. The concrete piers were j^rottcted from the heat of the boiler fires b\' means 
of asbestos felt, but the author's experience is that no j^rottction is needed even against 
the actual heat of hot fuel. Reinforced concrete bunkers should app(\al to a large 
number of engineers as being at once a very economical method of storing coal for many 
minor purposes, such as mechanical stoker feeding, as well as hand stoking. Low m 
first cost, and with advantage of a negligible charge for upkeep, it can be safelv said 
that for coal storage ])urj)Oses the use of reinforced concrete is bound to b^con^e universal. 



281 



NEW WORKS IN CONCRETE. 



ICDNCBETEJ 



NEW WORKS IN CONCRETE 

AT HOME AND ABROAD, 

Under this heading reliable information 'will be presented of neio tvorks in course or 
construction or completed, and the examples selected ivill be from all parts of the ivorld. 
It is not the intention to describe these 'works in detail, but rather to indicate their existence 
and illustrate their primary features, at the most explaining the idea "which ser'ved as a basis 
for the design. — ED. 



CONCRETE BLOCKS AT PORT TALBOT. 

In connection with the various improvements and extensions that have been made at 
Port Talbot and which are at present in hand, it is interesting to note the use of concrete. 
blocks by the Port Talbot Railway and Docks Co. for the erection of their new hydraulic 
power station buildings. In the accompan\ing illustrations are shown some of the work 
which was carried out in hollow slabs. The buildings comprise the following : — 

Hydraulic power station 97 ft. long by 57 ft. wide by 30 ft. to eaves. 

Boiler house 97 ft. long by 57 ft. wide by 24 ft. to eaves. 

Electric engine house 47 ft. long by 31 ft. wide by 19 ft. to eaves. 

Economiser building 6g ft. long by 34 ft. wide b.v 17 ft. 6 in. to eaves. 




CoNCRETK Block Hlii.ihm;^ 1 ok iiu. I'cjkt Talhot Duck Cu 



'i'h(.- bl(;cks and slabs us( d throughout were " Wingel " blocks, made on " Winget " 
machines. The centres ol stanchions vary from 10 fi. to 14 ft. The i)anel walls be- 
tween the stanchions are built entirely of 4H-in. hollow blocks from groimd to eaves and 
ridges, and are of th<' sam<- thickness throughout without anv ste<'l r<'inforc<'nu'nts of 
any kind, with the cxC'Cption of the r<inforc<'d concrel<' still carried across the stanchion 
foundations to supjjort the walls. 

The engineer to the Port Talhol I\ailwa\' and Docks Co., Ltd., is Mr. W. Cleaver» 
M. Inst.C.K., under whose su|)ervision this work was carried out. 



28 



m 



, CTONMPIK TiaNAl, 
LN(iINKLRlNt> ^ 



CONCRETE BLOCK BUILDINGS. 



PLACING OF CONCRETE FOR DOME OF MELBOURNE PUBLIC LIBRARY. 

In our l)<"cNinlHr luiinlxr \vr i)ul)lishr(l a short dcsci i|)lioii of th<' donu* for the 
M<'ll)OiiriU' Public Lihr.iry. We tur now ;ibl<' to puhlisli ;i few furth<-r j);irti(ulars 
re^ardinf^ the new Reading Room, which was opened towards the end of last year. 
Our notes have sinvial r<'f(r(ne<' lo ihr placing ol lh<- (■on(r<'te in |)osilion. 'I"h<- nyw 
readinLj-rooni, situated on ihc tii>l-lloor level of the building, is 115 fl. across from side 
to side of the oetaj^on, i^ivinj^ a lloor ar<-a of io,()57 sq. ft. between the inner walls, with 
a ck'ar heij^ht of Soft, from readin^-rooni lloor to lh<- sprin^in«^ line of ihc doni<-. 'I"li<- 
clear height from reading-room lloor to ajx'X of donn- is ii()ft., and tli<- li(i<^lit from 
basenKMit of buildinij to ajx'x of dom<' 150 fl. 

For the i)uri)ose of |)lacin<f the concret<' a platform about 20 ft. squar<' was er<'et<d 
above the central lantern li^ht and carrie^d by the timber centerinj^ b<'low. The mate- 
rials used for the concrete were 1 ])nrt cement, 2 parts good coars<' sand (specially 
sel<x:ted), 3 parts bluestone screeninj^s up to f in. gauj^e. These materials were stored 
in basement, so as to have no stoppai^e of work due to shortage of material, and wen* 
mixed bv hand in a thorough manner in the baseuK-nt, shovelled into trucks, which 




v\'-\a- h- 


"•^J«* 


1 




9^^ 


A 



Concrete Block Buildings for the Port Talbot Dock Co. 

were immediately wheeled on to the cage of an electric hoist and thus lifted up to the 
platform level above the dome. The concrete was dumped from the trucks on to the 
platform and immediately shovelled by hand through hoppers in the floor of the plat- 
form, discharging into the heads of chutes, by means of which it was conveyed by 
gravity to the various positions required on the dome. These chutes were made in 
portable lengths of sheet iron with a timber support to bottom thereof, and were 12 in. 
wide by 5 in. deep. The sloj>e of the chutes was approximately 30° to the horizontal, 
and it was found that the concrete, which was mixed fairly wet, ran down the chutes 
evenly and without any segregation of the constituents. The concrete was discharged 
directly into the position desired, where it was continuously rammed and spaded into 
position round the reinforcing bars. In this way about 8 cub. yd. of concrete was 
placed per hour. In placing the concrete the buttresses were done first, followed by 
the heavy ring at the springing of the dome, suitable toothings and skewbacks being 
left to take the concrete to be placed subsequently. In placing the concrete in the ribs 
of the dome the eight main angle ribs were done first ; the diametrically opposed ribs 



283 



NEW WORKS IN CONCRETE. 



ICQNCBETEJ 




Concrete Shute. 



work, which was kept wet by 
the application of water, the 
whole of the exterior face of 
the dome was cemented with 
3 parts siind and i part cement 
and finished with a steel 
trowelled surface. 

The timber centering was 
left in position for four month? 
after concreting was finished, 
and was then gradually eased 
by slacking off the wedges on 
top of the wood trusses ; these 
were slacked off from the 
springing, first working to- 
wards the centre. It was found 
that these wedges came away 
easily, apparently carrying 
little weight, no doubt due to 
the gradual shrinkage of the 
timber. The total downward 
deflection of the apex of the 
dome on the removal of the 
centering was ^^ in. This was 
measured by taking readings 
on a graduated rod sus|Knd<'d 
from the apex of the dome by 
means of a surveyor's level sta- 
tioned on the flat roof over the 
annulus. This deflection re- 
284 



and portions of the adjacent 
purlins and slab were carried 
up simultaneously from the 
springing to within 4 ft. of the 
ring at the apex during each 
dav. The eight intermediate 
ribs were then similarly con- 
structed, this bringing all the 
ribs up to within 4 ft. of the 
ring at the apex. The concrete 
to all ribs was stopped with a 
face at right angles to the axis 
of the rib at that point and 
additional rods put in projecting 
beyond the face to give addi- 
tional bond to the new concrete. 

The concrete ring at the 
apex was then placed in one 
day, special care being taken 
to get a good bond with the 
upper faces of the ribs by cut- 
ting same back and well grout- 
ing in cement mortar. 

The concreting of the re- 
maining portions of the pur- 
lins, the dome slab, 6 in. thick, 
and the walls of the lantern 
light was then proceeded with. 

As soon as possible after 
the completion of the concrete 




\'iew lookinti up at Central Lantern Light, showing Timberin»4 for Dome 

MeLBOURNK PlHLIC LiBRAKV. 



/^y,CONMl?lJCTION' A Tj 
l» V KNCilNt-l-PINd — J 



COSCRETE nriLDINGS AT NORWICH. 



in.iiiKcl i-oiisi.inl lor llint d.ivs, \\ hrii il w.is found ncccss.uv (o i<ii)()\c the rod. Up 
to th<' pii'sint tli<' donu' has stood \\<II. 

The contractors for the work were Messrs, Swanson Hrothcrs, master IniildcTS, 
who carried out this extensi\e and diflicuh work very satisfactorih', and the structural 
work was under th<' su|w'rvision of Mr, ('has, P. Smart, B.C.E., of th<' firm of Hat<'S, 
Pcebk's ;uul Smaii, the archit<'Cts for lh<' huikliiii^, and wh- ,ar<' ind<'bt<'d to him for 
these additional particulars, 

CONCRETE BUILDINGS AT NORWICH. 

The accomprmyinLi two ilUisirations show .some small concnte huildinj^s recently 
erected at Norwich by Mr, .\rthur Collins, the City Eni^in<'er, to whom w<' are ind<bted 
foi our photoj4raj)hs, Th<' buildini^s are useful in >howin_<4 the application of concrete 
and reinforced conci'ete for small l)uildini>s. 




! in 11 1 1) ] 





Concrete Dwelling-House for Foreman Engineer 
AT Norwich M.mn Sewage Pl.mping Station. 



Reinforced Concrete Urinal at 
Norwich. 



28 



NEW BOOKS. 



ICQNCBETF] 



NEW BOOKS 

AT HOME AND ABROAD. 

A shjrt sjrn-mry of some of the leaiing books 'which hax>e appeared during the last few months. 



"Concrete Products" by " Hollie." 

London. The An.'^lo-Gerinan Publishing Co., 15 Craven 
Street, Strand, W C. 125 p.). 

This little volume has much to recom- 
mend it on account of the very practical 
manner in which it is written, and the 
author has imparted a freshness to his 
work which is seldom nzei. with, and which 
renders the book very interesting to read. 

Before dealing with the matters de- 
scribed in the book, we should like to draw 
the author's attention to a remark made 
by him in the preface — viz., " There is not 
a single English book dealing with this 
branch of industry. All the information a 
man interested in concrete can obtain is an 
occasional article in one or other of the 
building journals." We were under the 
impression that our journal dealt very fully 
with all kinds of concrete work, and that 
we {)ublished more than an occasional 
article on this matter, but either we are 
mistaken or the author has not studied 
the premier journal devoted to his special 
subject. 

Facts and comparisons are drawn 
between concrete bricks and clay bricks, 
and although we are advocates of con- 
crete, we are afraid that the writer has 
somewhat missed the essential points, 
especially when dealing with the question 
of appearance, as the artistic taste has not 
b'-en considered, and the very irregularity 
of a clay brick in colour and shape is the 
thing which appeals to the architect, and 
after all he is the j)erson who adopts and 
specifies the material to be used. 

We would call the author's altcntion to 
the l.'illcr [jirt of page 7, where he sa\s . 
*' .Measure and examine it whichever wax 
you ccjncretc blocks op|)osile." 'ihcrc is 
<vif|(nll\ something wrong liei'e, ;iii(l w ( 
fail lo see the author's meaning. 

( 'oinj)arisons are drawn between nt arh 
all classes of concrete i-rtxlucls ;ind llio-e 
produced in other materials, and the .-.d- 
vantage* o'i concrete are ver'- strongh 
stated, but the writer in all eases is reckon- 
ing without the ?tsthetic instincts of the 
Irue designer. The various materials use, I 

286 



in the making of concrete are dealt with 
in detail, and the plant required for the 
production of various commercial forms 
of concrete is described and illustrated 
with many useful recommendations. 

In dealing with partition slabs the 
author does not mention the all-important 
fact of allowing these to become thor- 
oughly seasoned before they are used in 
the work. These slabs have become very 
unpopular with many architects solely on 
account of un. easoned slabs being used, 
with the result that contraction takes place 
afterwards and cracks appear in the work, 
whereas this is not the case with the 
various hollow brick partitions. There is 
no need for this unpopularity if manufac- 
turers will only see that their products are 
fit for use when delivered to the site. 

The book is well illustrated throughout, 
and despite our criticisms we recommend 
it to our readers as being well written and 
full of interesting information, which is 
presented in a style quite different from 
that found in most technical works. 

Fire Tests with Floors. 

A Floor of Reinforced Concrete reinforced with 
Triangular Re nforcemsnt and presented for test by 
Messrs. Naylor Bros.. Huddersfield. Red Rook, No. 
18S of the British Fire Prevention Commitiee. 

Published at the offices of the Coneni tee, 8 Waterloo 
Place, London, S.W. 

At a lime when the question of rein- 
forced concrete is largel}- before the 
technical professions, and the question of 
regulating such structures is receiving the 
all<'ntion of the public authorities con- 
cerned, a Report issued by The British 
V\n- Prevention Committee (as Red Book 
No. iSS) dealing with a fire test on a re- 
inforced concrete fioor with triangular 
lattice reinforcement may be detMiK^d lo be 
of special interest. 

The |)refatory note to the Re|)ort indi- 
cates th.il in c()mj)arison with other fioor 
tests, I he inslructi\'e feature of this invesl'- 
galion is that granite chip|)ings do not 
appear so satisfactory from the fire point of 
\i( w as some of the other materials that 
ha\c been used in the Committee's tests, 
and fiirlher, thai the question of j)rotecting 



J, coNM pnc-naNAi> 



NEW BOOKS. 



tlic solVil of tlic icinforccd CDiicii'lf bi-ains 
rcciuiics cMrclul .ittontion. 

1 1 s|)i;iks well for ihc syslcin of con- 
st luct ion and the form of reinforcement 
useil tliat, iCi^ariUess of what appears lo 
have been an imsatisfaiioi y concrete 
ai^^re^i^ati', the lloor stood up so well and 
obtained The Rritish Vwc PicN-ention Com- 
milte(>'s classillcation of " b\dl Protectitjn, 
(Mass I>," which means a 4-hoiir test willi 
lemj)eratures reachinj4 i,SooOI"., followed 
b\' th(^ aj)plication of water from a steam 
lire enj^ine, and it is obvious that if a 
better form of concrete had been used, and 
the question of j)rotection had received 
more consideration,, an even better result 
with less deflection must have been 
obtained — i.e., a result that would have 
practically left the floor in such a condition 
that it need not be taken down for rein- 
statement after a severe fire. 

The British Fire Prevention Committee 
is testini^ one or two large floors every 
vear, and, apart from the non-proprietary 
svstems of construction that they have 
tested, a number of patented systems have 
now obtained the highest classification, 
which gives them a special claim for em- 
ployment by the public authorities and cor- 
porations with whom safety from fire is a 
matter of importance. 



Some ihirts floors h.ive now been tested 
l)\ the ( ■onnnittee, of which about half 
were proprietai'v floors, ;md half floors in 
common use. 

"Transactions and Notes of the Concrete 
Institute." Vol. v., Part I. 

l'iil)lislie<l at Denison House, 296 N'auxhal! lirid^e 
Koad. S.W. 

This volume in its |)reliminary page's 
contains some notes regarding the member- 
ship of the Institute and contributions lo 
its library. A new feature is the short 
review given of new books received. 'I'he 
remainder of the volume contains the 
papers read at the meetings of the Insti- 
tute, together with a verbatim report of 
Vhe discussions. The papers here dealt with 
refer to the " Settlement of Solids in Water 
.and its Bearing on Concrete Work," by 
Dr. J. S. Owens; " Steel Frame Buildings 
in London," by Mr. S. Byland<'r; 
" Economv in Reinforced Concrete 
Design," iDy Mr. J. A. Daveni)ort ; "The 
Strength of Cement," by Mr. H. C. John- 
son; "Props and Beams in Mines," by 
Prof. Stephen M. Dixon, and two reports 
of the Reinforced Concrete Standing Com- 
mittee. All these have been dealt with in 
summary, with extracts from our repor) 
on the discussion, in our journal. 



,"** 



287 



MEMORANDA. 



EaNCKETE' 




Memoranda and Neivs Items are presented under this heading, ivith occasional editorial 
comment. Authentic neivs ivill be tvelcome. — ED. 



The Maachester Building Trades' Exiiibition.—X Building Trades' Exhibition 
was held last month in Manchester under the auspices of the various local Building 
Associations. The Exhibition was opened by the Lord Mayor of Manchester. There 
were manv features of interest, but it would be impossible to make reference to the 
manv exhibits shown, and we must therefore confine our reference to just a few which 
are of special interest to readers of this journal. Among those who exhibited were : — 

Messrs. Bells United Asbestos Co. {Northern Agency), who showed their 
" Poilite " asbestos cement tiles and sheets. This material, as is known, can be used for 
roofing tiles, for walls, and ceilings, etc. The exhibit in this instance also showed the 
roofing material actually as applied to different classes of buildings. 

The British Fibro Cement Works, Erith, showed a simple type of building 
roofed with their patent " Fibrocement " slates. 

The British Portland Ce)nent Manufacturers, Ltd., London, E.G., had a most 
interesting stall, which was primarily of an educative description, and the ever-in- 
creasing uses for Portland cement were adequately illustrated. The Company showed 
reinforced concrete fence posts and fencing, concrete drain pipes, and every kind of 
garden ornament such as flower vases, columns, etc. The use of concrete on the farm 
and estate was also shown and demonstrated. The exhibits also included briquettes, 
cubes, examples of suitable and unsuitable aggregates for mixing Portland cement, and 
also apparata for determining the voids in aggregates. 

The Cyclops Concrete Equipment Co., Manchester, exhibited their concrete 
block and other machines. 

Messrs. Ironite, Ltd., London, exhibited their waterj)roofing material for render- 
ing waterproof structures such as tanks, reservoirs, tunnels, pits, etc., where there is 
heavy water pressure. The material can also be a|)plied to floors, roofs, fencing, etc. 

Messrs. Sano, Ltd., of Manchestc'r, exhibited their jointless composite flooring 
and wall covering, and which can be laid on every kind of floor. 

Messrs. Vulcanite, Ltd., showed the various ways in which their vulcanite water- 
proofing material could be used. The principal feature of their exhibit was a model 
swimming bath watcrjjroofed with vulcanite lining. 

Some New German Regulations Regarding Reinforced Concrete.— New regula- 
tions were issued last November by th(; Berlin Police Authority for the construction of 
reinforced concrete ribbed floors that is, of floors constructed of reinforced concrete 
beams the f>anels between which are composed of bricks, hollow blocks, or specially 
devised objects in addition to the ordinary j)anel of reinforced concrete. Such systems 
of construction, mainly in patented forms, have come into frequent use in recent years, 
and special regulations for their use have thus become necessary. The regulations of 
May, 1907, have therefore been modified and extended in some particulars so as to 
cover the new conditions. 

The use of hollow blocks, etc., cemented together but without the use of a reinforced 
concrete panel, is nol (xrinilted. '|"he llii(-kness of llie panel was \]\{'<.\ l)\ the regulations 
of 1907 at a mininuim of X cm. (3] in.), but where the filling blocks are rigidly united 
by pure cement mortar, it is permissible to reduce this to 6 cm. (2^ in.). 'J'he shearing 

288 



l^^i^SiS y^ MEMORANDA. 

stresses .ire lo he drtennined loi ilic iliiniirsi p.iii (»l ilic 111), .111(1 where ihi^ is so small 
that tht eoiuicte imm (inl\ l)f easl, must not txcird j-^; Ui^. (in.-, I)iil w her( thorou^li 
raininiiij^ i^^ |)()ssihle, u|) to 4*5 kj^./em.- nia\ l)e allowed. 

As a rule, each rih is to he leinhiued with one rod, .and only when I he hre.idlh of 
the rih .It the l(\el of the 1 cinfoi i-cinciit exceeds () (in. is .1 greater numher of rods 
allowid. When eoin|)utin^ the dist.aiue hetweeii the rods and the lower surface of the 
he.ani, the ihiekness of .in\ plate w hieh is attached for the purpose of ^ivinj^ a smooth 
und'i- sui f.ice is lo he inclu(led. The rihhed Hoor nuisl heir on the sup|)ortinj4 walls at 
least 1 ^ cm. (5', in.), and nuist not he emploxed .as .a stilTenini^ mendxr. The ribs arc 
not to he furthei- .ap.ii t th.aii ()o cm. (j ft.) from centre to centre, except where the fijlinj^ 
material is j4roo\ed hlocks of .1 >peci.il t\|)e, ceuK-nted together, when the distance 
ma\- ho extended lo 75 cm. {2 ft. () in.). In dwellinj^ houses, floors with exposed ribs 
must leceixe a tinishin<4 coat of cement. 

h^loors huill into the walls on each side must he computed with a moment of ^ 

8 
hut in special cases, when the erection of walls and Hoor proceeds simultaneously and 

pi- 
the lixini; is siiown to he surficieiit, a moment of 'j- ma\- he assumed. In such a case 

alternateh" one reinforcing; rod must he ixnt u|) and the other carried on. 

Where ribbed tloors are continuous over several spans the same rules apply as with 
other reinforced concrete floors, jjrovided that the reinforcement is carried on con- 
tinuously. That is, the floor cannot be rej^arded as continuous when carried by steel 
beams, but only when carried bv reinforced concrete beams and projjerly constructed. 
For such floors, the bendin<> moment is to be calculated on the assumption that one 
span is fully loaded and the neighbouring spans unloaded, as long as the working load 
is below 1,000 kg. per square metre; with heavier loads the most unfavourable loading 
is to be assumed. Negative moments are to be computed as if both spans adjoining 
the bearing were fully loaded. 

Floors of the Koenen tv])e are to be computed with a constant moment of ^ for 

18 

middle spans and ^ for end spans, whether carried bv steel or reinforced concrete 

12 
beams. 

Certain other regulations, referring to special forms of construction, require 
drawings for their illustration. 

Port Talbot Dock Works. — In connection with the additional coal tipping and 
wharfage facilities at the above docks, it is interesting to note that reinforced concrete 
will be used largelv. A 900 ft. long reinforced concrete wharf is nearing completion, and 
a further wharf of reinforced concrete is under construction. An extension of 100 ft. 
is also being made to the Crown Fuel Works Wharf. We hope to give full particulars 
and illustrations in a later issue regarding the concrete and reinforced concrete work in 
connection with the improvements in hand at these docks. 

Reinforced Concrete and Rheumatism. — Our contemporary, the Builder, recently 
contained an article under the above heading, llie writer of the article states that :• — 

" There are a great many different fungi, which are all produced by spores falling 
upon favourable soils in favourable positions. There are a great many different forms 
of rheumatism, and they also are all produced by spores or micro-organisms. 

" Sunlight and dryness are unfavourable to the growth of the spores either of fungi 
or of rheumatism, while darkness and dampness seem to be favourable to the growth of 
them all. Therefore it will be wise to see that all human habitations shall at least be 
drv and light in order that no spores of any of these plants shall be produced in the 
vicinitv of mankind during the hours of leisure and of rest." 

He then quotes numerous cases which have come to his notice and attention. He 
states that the " modes of preventing the pre-existing enfeeblement of vitality which 
conduces to the catching of rheumatism are of course manifold." It is, however, pointed 
out that these methods are for the most part beyond the power of the physician to 
affect, but that the remedy lies rather with the architects and builders. The writer points 

2F9 




T^iiiSi;^^ 



''J<«B 



» -^""'^gp^ 



rY^lM(^I)17^rP j^CONSTRUCTIONAl^ 



XISGINBERITSTG 



*wiL 




COMPARE THE COST 

OF THAT TIMBER PILING YOU USED FOR YOUR 
LAST JOB WITH THE FOLLOWING— 




UNIVERSAL JOIST STEEL SHEET PILING 

43 lbs. per super foot when interlocked, on hire for your job 
at the approximate price of Is. lOd. per super foot. 




SIMPLEX STEEL SHEET PILING 

In two weights, i.e., 22 & 27 lbs. per super foot when inter- 
locked, on hire for your job at the approximate prices of 
lid. & Is, 3d. per super foot respectively. 

THEN REMEMBER 

THAT THE STRENGTH OF YOUR PILING IS THE 
STRENGTH OF ITS INTERLOCK — OUR PILING 
HAS AN INFINITELY STRONGER INTERLOCK 

THAN ANY OTHER. 



THE BRITISH STEEL PILING CO. 

4 DOCK HOUSE, BILLITER ST., 



Telephone — 

Avenue 5463 

Telegrams- 

Pilingdom, London. 



LONDON, E.C. 



v^/o/^/< .S.- 
ALBION & RAVENSBOURNE WORKS, DEPTFORD 



290 



Please mention this Journal 'u>hen ivritinq. 



J, CON.M kMKTlONAl, 



MEMORANDA 



!)u( lli.it it is the honn's of llic people wliith nuisi he kept free from the spore-hcirin^ 
coiulilions. In okIit to clTi'ii this we imisl " produce dw clliiif^s in which the conditions 
are inimical to the j^rowih of ^poic-heai iiij^ oij^anisms." The article continues: 
" If * the material interests of the suhj<(l races are the tfuidiiii^ principle of Imperial 
(ioxt'iiiment/ let the material interests of our |)eo|)le he the j^uidin^ princi|)le of our 
municipal authorities. Let the i ich huild of what materials they like; but let every 
munici|)alitv see that the woikman's dwcllini^s he im|)<rvious to wet and to cold and to 
vermin almost to llood an<l to earthquake and to lire. In fact, it should be built of 
ferro-concrete. Is there a ciieajx'i-, cleaner, slron;;4er, healthic r building material known 
to man ? 

The writer then |)oints out that as " warmth is essential to overcome on<' of tjie 
most prevalent ailments of our climate, and if ferro-concrete be a building material most 
iikelv to prove prejudicial to s|)ore-bearin^ diseases, but is too rapid a conductor of heat 
to make comfortable dwellings for mankind, it is up to the building profession and to 
those familiar with the multii)le requirements of the case to erect workmen's dwellinj^s 
of a non-porous solid that shall yet be not too quickly affected by atmospheric alterations 
of temj)erature, since every virtue has its failinff, and the sharpest knife must be 
handled with the j^reatest care. One of the faulty virtues of ferro-concrete is that it 
prevents the penetration not only of damp but of air, while those porous materials to 
which we have hitherto trusted for the buildinj^ of our homes have literally leaked at 
everv pore. We have been accustomed to respire throuj^h wall and ceiling and floor, 
while the wallpapers and plaster of our rooms, if not indeed the very bricks of the walls, 
have proved veritable filters of germs, letting out indeed noxious gases from our apart- 
ments but retaining with certainty (in the absence of visible openings) every germ for 
future potency of infection. 

" With the use of a non-porous building material all this automatic imperfection of 
ventilation must be exchanged for a purposeful system of architectural efficiency. 

" As smooth, cold surfaces are not conducive to comfort for leaning against at home, 
all ferro-concrete walls in the house should be lined with a porous and washable dado ; 
while parquetry flooring should replace the boards to which we have been too long 
accustomed. 

" Still greater warmth would be secured by double walls w'ith the necessary air 
space between, carefully secured from communicating at any point with the interior of 
the house; while a roughened surface to the outer w^all and a padded roof would com- 
plete the essentials of sanitary dwellings conducive neither to rheumatism nor rheu- 
matics." 

Scottish National Portrait Gallery. — H.M. Office of W^orks shortly propose re- 
constructing the Scottish National Portrait Gallery in Edinburgh, The gallery houses 
a very valuable collection, and the object of the scheme is to protect the building as far 
as possible from fire. Concrete floors covered with parquetry- will substitute the present 
wood flooring, and the roof will be of concrete. 

Concrete Electroliers.— A new concrete office building in Los Angeles has secured 
a very pleasing effect in its design by combining electroliers as a part of the architec- 
tural plan. These are of concrete and rise from the cornice in the building about lo ft. 
in height. They terminate in 5-ft. lights which form a cross. — Concrete Cement Age. 

A Concrete Village.— \ he Delaware, Lackawanna and Western Coal Co., of 
Pennsylvania, L'.S.A., have put up for their employes a model village, to be known as 
Concrete City, which forms an interesting example of a settlement of this kind. The 
houses are two-story structures, 50 ft. by 25 ft., built of concrete, with flat roofs and 
dark-green " trimmings." They are moulded in one piece. Floors, walls, roofs, stair- 
ways, even sinks and wash-basins, are said to be made of " poured " concrete. They 
are so constructed that, on occasion, the furniture may be all removed and the entire 
house thoroughly washed out with a hose. Each house contains seven rooms, and has 
stationary wash tubs, a buttery, and a good dry cellar. Wooden strips are embedded 
in the floors so that carpets mav be tacked down. Below the French windows, opening 
outward, window boxes for flowers are set in the walls. 

291 



MEMORANDA. [CaNCBETEj 

lINQUIRY.J 

To the Editor of Cosckkiv. and Constructional Engineering. 

I am presenlh- interested in the desion of a block of buildings. It is pro])Osed 
to run combined reinforced columns and pilasters up the outside of the building; these 
pilasters to be moulded, 

I shall be glad to know if you can give me any information as to suitable treatment 
of the external face of the pilasters to ensure that they will have evenness of colour and 
a smooth and artistic appearance after completion of the building. 

As vou are aware, the difficulty is usually to prevent patchy and white discolouration 
and also to prevent small surface cracks when the building has been up for some time. 

The pilasters, of course, could be washed over with cement grout or plastered with 
cement mortar, but it is proposed to discard both of those methods and to treat the 
concrete, after striking the boarding, either by rubbing down w^ith a float when the 
concrete is green, or by any other method to ensure a good external surface and appear- 
ance for the concrete. 

If vou can give me any advice as to this I shall be obliged. 

Yours faithfully, 

Enquirer. 

[REPLY.] 

If it is definitelv decided that no surface finish such as cement grout or cement and 
sand is to be applied, the only method we can suggest for obtaining a smooth surface 
is to have the shuttering very carefully and well constructed, with absolutely close joints, 
and a planed, clean surface towards the concrete. The latter should be carefully placed 
with fine stuff against the forms and no large aggregates should be allowed to get 
against the external faces. After the boarding is removed, the surface should be rubbed 
down with a steel float if the concrete is sufficiently green, or sandpaper or suitable 
stone mav be employed to rub off any projections. 

The Interim Report of the Concrete Institute on the Surface Treatment of 
Concrete, published in this journal last year, contains some useful information on the 
subject, and there are also some suggestions for surface finish in a book recently pub- 
lished entitled " Cassell's Reinforced Concrete." 

ERRATUM. 

We are asked bv Messrs. Edmond Coignet and Co. to say that through an oversight 
it was stated in their advertisement on page v. of our February and March issues that the 
new Law Courts at Jamaica were executed bv Messrs. Cowlin and Son, whereas this 
work was carried out by Messrs. Mais and Sant, of Jamaica. 



292 



CONCRETE 

AND 

COMSTRUCTIONAL ENGITSEERING 



k 



Volume IX. No. 5. LONDON, May, 1914. 

EDITORIAL NOTES. 



THE CONCRETE INSTITUTE. 
Public Opinion. 

Tin- Concrete Institute wns tlie subject of an extensive leadinj^ article in our 
last issue, with the result that we have received much correspondence reg-ardin^ 
its objects, its administration and its work. I<\irther, the " referendum " 
post-cards we issued with the April number, with the object of obtaining some 
idea as to the views of our readers regarding- the proposed change of the 
Institute's title and the change in its objects, have been returned to us in 
considerable numbeis, only one reader differing as to its tenor and about a 
dozen as to certam portions thereof. 

From the post-cards and correspondence, we realise that the general interest 
in the Concrete Institute's unfortunate doings is even greater among the public 
— i.e., non-members — than we anticipated, and that the broader and national 
aspects of its existence or failure appeal to a large section of the professional 
world and to a very substantial section of the industries directly and indirectly 
concerned. 

It thus appears to us, that if a section of the Council of the Concrete Insti- 
tute pursues its present course of pressing for a change in the Institute's primary 
objects, so that concrete and reinforced concrete only play a secondary part, the 
more influential section of the general membership — including practically all the 
professional members abroad and many in the provinces — will retire from it at 
the end of the current year, whilst even with its present constitution better work 
will have to be done in the interests of concrete and reinforced concrete on lines 
that do not lay themselves cpen to such frequent and justifiable criticism. 

The Institute's Administration. 

A change of President is impending through effluxion of time. It is to be 
hoped that, whoever the new President may be, he will take of^ce with the full 
confidence and good wishes of the Institute's Council as a whole, and not 
through any " arrangement " which would undermine confidence and be fatal to 
the Institute's prestige. There are rumours that something of this kind is being 
attempted. The Institute has had troubles enough without seeking this fresh 
one. On the other hand, a popular President of recognised standing and ad- 
ministrative ability could do much towards framing the Institute's policy and 
obtaining good management and courtesy towards its membership. 

Again, some of our provincial correspondents tell us that owing to some 
legal quibble they are not to be consulted on any change, present or future, in 

B 293 



THE CONCRETE INSTITUTE. [CQNCBETEJ 

the Institute, unless they happen to be temporarily staying- in London, or can 
afford the time and trouble to travel specially to town to record their vote. 
Some 250 members resident abroad are apparently to be kept in the same position. 
In other words, close on three-fifths of the Institute's membership is to be 
permanentl}- disfranchised at the behest of a section of the Council. Nothing- 
could be nK)re unwise than to offend the country and the Colonial member, no 
matter what the legal aspects of the Institute's rules may be. Why, even in 
public trading companies of standing- the member at a distance can generallv 
lodge a proxy, or if he cannot do so, is asked by courtesy to record his opinion 
in some informal way. 

GENERAL CONCRETE USES IN ITALY. 

In an earl\- issue of this journal we pointed to the readiness with which the 
Italian was using- concrete for every possible purpose. \'isiting- Italy this 
vear the traveller would be struck more than ever bv the increasing- use of 
Portland cement concrete for everyday requirements in town and country. 
Everywhere in Italy the praises of the material are being- sung- with no 
uncertain \ oice. 

Leaving- aside leg-itimate constructional work, where concrete now plays 
the premier role, one marvels at the adaptability of concrete where it is popular. 
Every form of sanitary appliance now appears to be made of concrete — the 
sewer, the pipe, the trap, the gully, the slop sink, the pantry sink and 
draining- "board," etc. It is used for pavement work, both for the 
roadway and the footpath, kerbs of every form, corner posts, lamp posts 
and tramway poles, refuse boxes and sandholders, electrical control boxes 
and fire alarm posts. Every little culvert, open drain, chute, etc., is being 
made in concrete. Again, the material is in use for fence posts, kilometre 
jX)Sts, and e\en signposts on the high roads, not to speak of seats and benches, 
horse troughs and ornamental fountains of excellent taste. 

The gardener appears to use it for rockeries, borders, and for all the odd 
jobs for which timber is generally the gardener's mainstay at home, such as 
props, shed work, frames. 

In many cases old iron rods, gas piping, barrel hoops are made use of as a 
rough-and-ready reinforcement, and by some intuition and rule of thumb they 
are generally placed in fairly suitable positions. 

\<> ad\'ocates of concrete, its ready application in town and country in 
Ital} is nrjw quite a revelation. We only wish the " handy man " in England 
w(Hild realise h(n\- econ(Mnical and jDractical is its application. Much lime and 
money would be saved and the wastefulness of constant painting, repairs and 
renewals avoided. 



294 




THE USHER HALL, EDINBURGH. 



THE USHER HALL of MUSIC, 
EDINBURGH. 



The special attention of our readers is called to the folloivinq article on the Edinburgh 
Usher Hall, otoing to the eitensi've use ivhich has been made of reinforcea concrete for a 
building to be used as a place of public entertainment. We ha've often divelt on the fire- 
res'Sting gualities of this form of construction — qualities so essential in a building of this 
description^ and ive 'would here like to draiv attention to the fact that the material lends 
itself ivell to dignified architectural treatment, as will be seen from a glance at the 
illustrations. — ED. . 

General Description. — One of the most important features in the 
construrlion of the recently opened Usher Hall, Edinburgh, is the extensive 
use which has been made of reinforced concrete. 

Reinforced concrete has been employed by the architects for the construction 
of the whole of the foundations of this structure ; a large portion of the retaining 
walls below ground level; the internal pillars supporting the heavy masonry outer 
drum wall and dome roof; the Grand Tier gallery in cantilever; the Upper Tier 
gallery in cantilexer ; the whole of the floors, beams and lintels ; the horizontal 
air ducts ; and the roofs. To such an extent has reinforced concrete been used 
in the design of this hall that it may be said that the whole of the interior acts 
as one monolithic mass, clothed by the outer architectural walls of stone. 

The style of architecture may be termed " English Renaissance " and the 
exterior is simple and dignified. 

Above the base course, which is of grey Aberdeen granite, the outer walls 
are of cream coloured Darney sand stone. A view of the exterior of the hall 
is shown in the Frontispiece. 

The hall covers an area of approximately 28,500 sq. ft., and is surmounted 
by a dome which rises to a total external height above the lower foundation level 
of 113 ft. Internally, the apparent height of the auditorium is limited to 60 ft. 
by the introduction of a flat plastered panelled ceiling, for acoustic reasons. 
The internal diameter of the circle formed by the outer drum wall enclosing the 
auditorium is 117 ft. The length from the front of the concert platform to the 
back of the Grand Tier gallery on the centre line of the building is 93 ft. and to 
the back of the Upper Tier gallery 104 ft. The proscenium opening is 65 ft. wide 
and has a depth of 60 ft., in which there is an intake to the concert platform 
on each side, making the width of the orchestra at the organ front 48 ft. 
Behind that is the organ chamber, 42 ft. by 18 ft. in size. 

There are two foyers on the Grand Tier level, each 38 ft. by 22 ft. 6 in., 
and a central crush hall, also 38 ft. by 21, ft. 6 in. The circular corridor, from 
which there are Ave large access doors to the auditorium, is 9 ft. in breadth 
and has a total length on the circle of 280 ft. At the ends of the corridor — 
one at each end — are spacious cloak rooms, each 38 ft. by 15 ft. The foyers 

B 2 295 



THE USHER HALL, EDINBURGH. 



ICQNCBETEJ 




Photographer, F. C. Inglis, Edinburgh.] 

Fig. 1. Interior of Hall looking towards Organ. 




Photographer, I-'. C. Inglis, lidinburgh.i 

l-'iU 2. Interior of Hall showing Cantilevered Galleries. 
Tin; DsHEK Hali- oi- Music, Edinhuroh. 
296 



r J, C-ONMU'DC-llONAl. 
L<V E,N(.lNht.RlNt. — -. 



THE USHER HALL, EDINBURGH. 



and (Miish halls arc Hocifil with rcinfoicfd concicti' coxricd uilli niarhlc. The 
cloak looins and corridor arc llooicd willi rc"mlor(H'd concrete coscrcd with 
|)olislicd oak l)locI< llooiiiii^. 

The arranjLjcn-icnl ol the entrance hall, ciiish halls, cloak rooms and corridor 
are the same in all i-es|)ects on the j^ronnd l1oor as on the level of the (irand 
'\"\cv. On the I'jjpi-r Tier i^allery Icxcl theic are li\i' crush halls, three in the 
(\'ntre, loadino- from one to the other, each v^ ft. by j.|. ft., and all lighted by 
ir.eans of dome lii^hts from tlu' rool. The crush halls at the ends of the gallery 
corridor are each 49 fl. b\- 15 ft., and are similarly lighted. 

On each side of the (M)ncert |)latform at the east end of the hall are spacious 
retirini*' rooms for singers, instrumentalists, etc. 

There is also <i wide circular corridor beneath the raised tiers of scats 
in the orchestra, with a stair opening- for artistes leading directly up into the 
centre of the concert platform. 

On the top Hat there is a large kitchen and scullery accommodation. 

Under the concert platform, and separated from the remainder of the 
hall by means of a reinforced concrete floor, there is a sunk basement cover- 
ing- approximately 6,800 sq. ft., which is (xrcupied as a boiler house in 
connection with the heating- apparatus, and as mechanics' workshop, chair 
store, and extraction fan house for the ventilation of the hall. 

The extraction fan exhausts from a circular underg-round duct con- 
structed of reinforced concrete, and running- round the auditorium, into which 
the vitiated air from the hall is drawn and exhausted outside into the open. 
This duct is 8 ft. 6 in. square internally, and has a total length of 290 ft. 
The chamber for the intake, purifying-, and heating- of fresh air for the supplv 
of the hall (known as the " Plenum Chamber ") is placed on part of the roof 
of the Upper Tier g-ailery crush halls at the Cambridge Street Lane side of 
the building-, and the outer walls of this chamber, which is circular in form, 
are constructed of heavy masonr}- in keeping- with the remainder of the 
building-. 

The internal floors and roof of the Plenum Chamber are constructed of 
reinforced concrete, and the whole dead load of this structure, which is of 
two stories in heig-ht, and including- the heavy masonry walls, the reinforced 
concrete floors, roof, and heavy machinery installed therein, are wholly sup- 
ported on a system of reinforced concrete beaming at roof level of the 
crush halls. It ma} be mentioned that the Plenum Chamber contains two 
powerful fans driven by electro motors, and also batteries of radiators for 
heating- the air. The air, after being- purified and heated, is driven throug-h 
openings in the flat plaster ceiling under the dome into the auditorium. The 
crush halls, cloak rooms, and corridors are heated b} means of radiators. 

The stairways at the front entrances to the hall are constructed of rein- 
forced concrete and covered with marble. The remainder of the various inside 
staircases are constructed of Leoch stone, and, where necessary, are supported 
by a system of reinforced concrete stringer beams. 

In the auditorium the fronts of both the Grand Tier gallery and Upper 
1 ler gallery are of horse-shoe design, and are constructed entirely of rein- 
forced concrete covered with fibrous plaster. 

The reinforced concrete degrees of both cantilever galleries have been 
covered with oak flooring. 297 



THE USHER HALL, EDINBURGH. 



ICQNCKETEJ 



The i;:illcries and area are provided with tip-up seats. The floor of the area 
has a rake of 4 ft. <i in. from the last row of seats at the back to the 
platform. 

The level of floors at the back of the area therefore corresponds with 
the level of the platform. 

In ihe orchestra the seats rise in tiers, arranged in segmental form. 
The following is a summary of the seating accommodation: — Area 1,192, 
Grand Tier 428, Upper Tier 813, Orchestra 349, Platform 120; total, 2,902. 

The foregoing brief description gives an outline of the general arrange- 
ments of the hall. The interior of the auditorium, even when filled, gives an 




Photographer, F. C. Inglis, Edinburgh.] 

Fi'A. 3. View of Main Entrance Hall. 
The Usher IIaei. of Music, Edinburgh. 

impression of vaslness, due to the fact that the reinforced concrete galleries 
have been (onslruded ni cantilever. The adoption of the cantilever principle 
in the constructi(jn of the galleries is advantageous, as there is not a single 
pillar within the entire auditorium to obstruct the view of the concert platf')rm 
and organ from any seat in ih<' liall. 

Attention may be dire(Med to the photograj)hs which show the beautiful 
decorative effects obtained, showing that the architects have been aided rather 
than ham[)ered by the almost ex(lusi\<; use of reinforcx'd concrete in the struc- 
tural part of the work. 

The following is an appropriate sunnnary of lh( total cost of the hall and 
its site: — .Site, ^,36,000; buildings and lurnishings, ;^,"94,ooo ; organ and case, 
;^4,ooo. Total cost, ;£^ 134,000. 

Reinforced Concrete Work. — The reinforced concrete foundations were 
designed to spread the loading so as not to exceed a maximum pressure on the 

298 



[ 



J, fONM UUCniaNAl. 
C\ LN(,lMhl\yiNti — , 



TUB USHlik HALL, HDINBURGH. 



^rouiu' ol j; ions piT s(|uar(' fool, .md tlu- <;ciuTal arraii^cnicnl and rcinforci-- 
nuMit ()( tlusr fouiulatioiis is as shown on the working detail clrauin^ rcjirocku <-d 
in /'/.;:. 5. 

li is intiTestint^- l(» noti- tliat owinj^ to tlu- cart-ful <\'ilrulati()n and design 
of tlu'si' rcinfori't'd roncrc'ti- loundation> tlu-rc lias not been the slightest si^n 
ol" iine(]ual settUmrnt in thr whole of this ■extensixc structure, a matter of 
extreme imj-)oiianee to the eantile\er j^alleries in this building'-. 

h'rom tlu' loni^iludinal si'ction (F//;''. (^) it will he seen that a reinforced 
concrete ri'taininj^- wall has been constructed round the outer circle of the under- 
g-round air duct. This ri-inforced concrc'te wall is desi^'-ned to a(M not only 
as a retaining; wall but ?ilso as a foundation beam, servinj^" to distribute the 
isolated loads carried into it by the reinforced concrete pillars which spring from 
it at the level of the tloor o\ er the duct, supporting" the weight of the super- 
structure and main dome roof. For this reason a uniform thickness of 24 in. 
was adopted for this retaining" wall for its entire length of 290 ft. 

The construction of the underground air duct is completed b\- a reinforced 
concrete floor, 6 in. in thickness, this floor beings constructed to slope uniformly 
at either side with the slope of the internal area of the auditorium. The duct 
is 8 ft. 6 in. square internally. 

The reinforced concrete pillars on the outer drum wall supporting- the 
Grand Tier and Upper Tier cantilever g-alleries and floors, and also the main 
dome roof, are artistically clothed in Sienna marble. 

On the Grand Tier level the horizontal area of the gallery in cantilever 
projecting beyond the supporting inner drum wall is approximate!}' 3,100 sq. ft., 
and is supported by 28 reinforced concrete cantilever beams, the maximum 
outhang^ of these cantilever beams on the centre line of the building being- 
20 ft. 7 in. beyond the inner surface of the supporting- wall. These cantilever 
beams form one of the most interesting- features of the reinforced concrete work. 
Fig. 8 shows an elevation of part of a Grand Tier cantilever beam ; the 
maximum depth of these beams is 3 ft. 6 in., diminishing to 1 1 in. at the extreme 
outhang-. 

The web of the back portion of the cantilever beam is pierced by 3 openings, 
each I ft. 10 in. in diameter, for the passage of air in the duct under the Grand 
Tier corridor. 

The cantile\er beams are received into a continuous padstone beam 
2 ft. 4J in. in breadth by 5 ft. in depth constructed on the inner drum wall, and 
are " anchored " into the outer drum wall by similar padstone beams 2 ft. in 
breadth by 4 ft. 9 in. in depth. The cantilever beams are strutted behind the 
point of support on the inner drum wall by the air duct, which is formed by 
means of a continuous reinforced concrete floor 6 in. in thickness, the air duct 
liaving a depth of 2 ft. 8 in. and a breadth of 8 ft. jh in., and a lower con- 
tinuous reinforced concrete floor 4 in. in thickness. 

The upstand front of the gallery is constructed of reinforced concrete 4 in. 
in thickness curved both in the longitudinal direction following the sweep of the 
gallery and also vertically, and beneath the upstand front a strutting- beam 
6 in. broad by 8 in. deep, also following^ the sweep of the gallery front, is pro- 
vided between the extreme points of the cantilever beams. 

For further security an additional reinforced concrete strutting beam 6 in. 

299 



THE USHER HALL, EDINBURGH. 



[QQNCBETEJ 



by 12 in. is provided between the cantilever beams at the centre of the span of 
the outhang- of the cantilevers and at their lower edge. 

The horizontal portion of the reinforced concrete degrees of the seated 
portion of the Grand Tier gallery is 3 in. in thickness, and the vertical breasts 




PJlot<)^ir(lphcl , I'. C Innlis, luliiibitrnlt.\ 

VnX. }. \'iew of Corridor. 
Thk I'siiEK Hai.l uv Misic, Edinburgh. 

are 4 in. in tliickness, the lallcr being const rucled as beams and the former 
as floor slabs supported between these beams. 

The xertical breasts arc also jiuKiioned with the upper portion of the 
cantile\er beams in a secure manner, and serve as struts between these beams. 

A reference to the longitudinal section, f Z^''. <), will show that ri'inforced 
concrete lintels were jjrovided over the doorways giving access to the area of 

300 



A' 



CiONMUMK-nONAl, 



THE USflER HALL, EDLVBURGH. 




301 



THE USHER HALL, EDINBURGH. 




ICDNCBETE] 

the auditorium, 
and as these lintels 
had to support the 
loading from both 
the Grand Tier and 
Upper Tier gal- 
leries, they had to 
be of exceptional 
strength. Their 
section is 2 ft. 3 in. 
broad by 3 ft. in 
depth. 

A photo- 
graphic view of the 
underside of the 
Grand Tier gallery 
showing the canti- 
ai lever beams, 
g degrees, struttmg 
§ 5 beams, and con- 
1 ^ tinuous padstone 
-^ ^ beam, and lintels 
^ s on inner drum wall 
i o is shown by Fig. 9. 
J 5 This photograph 
^ ^ was taken imme- 
yj^ X diately after the 
removal of the cen- 
H tering under the 
Grand Tier gallery. 
Fig. 10 shows 
a photog r a p h i c 
view of the center- 
ing in position for 
the construction of 
the Upper Tier 
gallery. 

There are two 
staircases leading 
from the main en- 
trance hall to the 
Grand Tier crush 
hall, each 7 ft. 3 in. 
in width, and 
having the treads 
and landings con- 
structed in rein- 



forced 

30 



concrete also covered with marble. 
2 



J, tONMUlR-nONAi: 
£Vt,N( 11 MhKklNt. ^, 



THE USHHR HALL, EDINBURGH. 



riu' r|)i)(i 1 HI i^alkrv rovers npproxinialcly .'iii area of 4,400 sq. ft., and 
is suj)portr{l 1)\- j() i cinforccd coiu rt'tc canlilfxcr iK'anis. 'Iliis ^^allcry has a 
maxinuiin lioii/ontal projection in cantilever of 13 ft. H in. beyond the inner 
(hum suj)j)oi tiiiL; wall, heinj^ considerably less than that of the Grand Tier 
i^allerv l)elo\v, but is carried back on the rake over and beyond ihc inner drum 
wall to the outer drum wall, tlius affordini^'- a considerably larger seating*- area 
than on the Grand Tier. 




Fig. 7. Plan and Section of Roofing over Orchestra. 
The Usher Hall of Music, Edinburgh. 

The Upper Tier gallery cantilevers are also supported on the inner drum 
wall, and are anchored back into a heavy reinforced concrete continuous pad- 
stone beam in the outer drum wall, 2 ft. 3 in. bv 3 ft. 9I in. 

The reinforced concrete degrees and upstand front are formed in a similar 
manner to those on the Grand Tier. 

The horizontal landings of entrances to the Grand Tier gallery are 
constructed of reinforced concrete 6 in. in thickness, as also are the walls at 
either side of the entrances and the lofty "baffle " walls at the back of this 
gallery. 

303 



THE USHER HALL, EDINBURGH. 



ICQNCBETH 



The stairways at the five entrance doors leachng- from the corridors to this 
gallery are also constructed in reinforced concrete. 

The floors at the level of the Upper (lallery crush halls and corridors 
present several interesting- features. Towards the ends of the corridors at 
either side of the hall the outer drum wall changes direction from the pear- 




Fig. 8. Typical Grand Tier Cantilever. 




I'lti- 'J. View of Grand i ler Gallery from below on removal of centering. 

Thk IISHKK HaI.L oh MuSIC, EniNHtlRGH. 

shaped f<;rrn of ihc auditorium to a complete (Mrc^ie surmounted by the main 
domed vooL lo j)crmil of this change of direction the wall passes across the 
9 ft. corridor in a diagonal circled direction approximately 23 ft. in length, 
when it arri\es over the heavy brick butts, l)uilt solid from beneath, at the sides 
of the proscenium opening. 

The j)r<)blt'm j)r(!scntcd was the support of this wall 2 ft. 3 in. thiclv, rising 

304 



J , tt>NM k»l K -HON A I . 



THE USHER HALL, EDINBURGH. 



to ;i liiiL;l>t ul ^1 ft. .iliovf tin- conidoi lloor, and of llic reactions from the t1at 
anuTiti' and main domed r^ofs takini^" snpjxnt on this wall, without unduly 
intcTJcrino- with the lu-adroon in liic main corridor of tlu- (irand Tier l<-vcl 
luMuath. This was ilftctrd hv a sjH'cial sxstcm of riinforccnicnt in the corridor 
lloor at rj)|)ir I i<r level lor a total length oi 29 ft. on cither side of the hall, 
the tt)tal depth of the reinforced concrete lloor supportinj^" the severe loadin^r 
thus imposed on it hein^ confineil to iH in., giving 13 ft. of headroom in the 
(irand Tier corridor below. 

Further interesting' features (»f the reinforced concrete construction at this 
level are the lloors over the crush h.all and foyers on the Grand Tier level below. 
These floors are formed by flat slabs 38 ft. by 23 ft. 6 in. and 12 in. in thickness 
without projecting beams. 

The reinforced concrete roofs over the orchestra and organ present unique 
features, as will be seen by a reference to Fig. 7, showing the method of 
construction of these roofs in plan and also in section. 

The roof over the orchestra had to be centred from the level of the base- 
ment, an average height of 60 ft. 

The construction of these roofs is carried out at three different levels : — 

{a) To auditorium side of beam A slab 9 in. in thickness, projecting partly 
in cantilever beyond beams A and B trained to follow the circumference 
of the main domed roof. 

{h) Between beams A and D slab 4 in. in thickness, with a system of 
tertiary beams E, and secondary beams C. 

(c) Over organ. Slab 6 in. in thickness. Maximum free span t^ ft. 8|^ in. 

It will be noted from the sectional draw'ing that in addition to the ends of 
beams A and B being stayed by the padstone beams at both supports, strong 
reinforced concrete gusset pieces have been introduced over beams C at their 
junction with beam A. 

The main beam A, in addition to the reinforced concrete roofs, over a span 
of 62 ft. 6 in., supports the solid masonry wall of the dome to a height of 
6 ft. 6 in. above the beam, along with a heavy projecting masonry cornice and 
four roof principals of the main domed roof. 

The roofs over the gallery crush halls are all of special type, as can be 
seen by reference to the longitudinal section. Fig. 6. 

These roofs are constructed with the reinforced concrete beams above the 
roof slabs, the object of this being to avoid any beaming appearing below the 
ceiling line. 

A reference to the longitudinal section of the building {Fig. 6) will show- 
that immediately below the masonry cornice of the outer drum wall a continuous 
reinforced concrete beam was constructed. 

This beam has a depth of 2 ft. 6 in., and varies in breadth from loi in. to 
I ft. 6 in., and is continuous right round the complete circle of the outer drum 
wall supporting the main domed roof, and has therefore a total length of 370 ft. 

It serves the purpose of (i) forming a complete circular tie round the dome; 
(2) spreading the isolated loads on the masonry from the principals of the main 
domed roof; and (3) forming lintel beams over the clerestory window openings 
into the back of the Upper Tier gallery. 



THE USHER HALL, EDINBURGH. 



ICDNCBETEJ 



In conclusion of this necessarily restricted description, it may be stated 
that approximatclv 300 tons of steel and 6,000 tons of concrete were required 
for the reinforced concrete constructional work. 

Summary. — The interior of the hall has a very attractive aspect. Its 
constructive lines are pleasing- and satisfactory, and it is well proportioned in 
respect of height, width, and depth. 

The scheme of decoration ot the auditorium and orchestra in white and gold 
also satisfies by its simplicity and refinement, and the marble and bronze work 
of the entrance and crush halls and foyers are in similar excellent taste. 




Y'xu.. 10. Temporary Centerinj^ of Upper Tier Gallery in position. 
Thk Usher Hall of Music, Edinburgh 

The acoustics of the hall have been proved to be perfect, and this is to be 
specially noted in view of the extensive use which has been made of reinforced 
concrete construction. 

The architects for the hall are Messrs. Stockdale Harrison and Sons, and 
M. H. Thomson, T". R.I.B.A., Leicester. 

\u the (i<;sign of llie reinforced concrete constructional work the architects 
ass(x:iated with them .Messrs. F. A. Macdonald and Partners, consulting- 
eng-ineers, 135, W(;llington Street, Glasg-ow, and the close co-operation which 
has been uniformly maintained between the architects and the reinforced 
concrete eng-ineers ever since the first desig-ns were made in September, 1910, 
has materially helped in the < lucidation of many complex structural problems. 



306 



(9. CON.VTkM TC-IION A I :| 



RHINFORCHMHNr IN HRAMS, 




1 



SHEARING OR DIAGONAL 
TENSION REINFORCE- 
MENT IN BEAMS, 



By CHARLES F MARSH. M.lnst.C.E. 

The folloivrng article should be of special interest to engineers and others 'who 
study this important question — ED. 

GENERAL OBSERVATIONS. 

When loiiifitudinal tensile reinforctnnents are bent up it is necessary to ascertain that 
the bending moment is sufficiently reduced at the point of bending to allow of the 
bending up of the bars. 

All bent up bars should be bent over at the top and continued along the upper 
surface and finished with a hooked end having an internal radius of at least twice the 
diameter of the least side of the bar, or otherwise securely anchored. They are some- 
times carried well into the portion of the beam acting in compression and Hnished with a 
hooked end, or, better still, hooked over a bar placed near the compressive surface, the 
hook fitting against the surface of the anchorage bar. These methods of anchorage 
apply also to special inclined or vertical bars. An alternative method of placing these 
bars is to hook their ends around the longitudinal tensile reinforcements and make them 
continuous through the portion of the beam under compression. This method is the 
reversal of the usual practice, but is advisable since it gives a good anchorage in the 
compressive portion of the beam. 

When longitudinal tensile bars are bent up it is advisable to make the bends with 
as large a radius as possible in order that the compression on the concrete at the point 
of bending may be reduced as much as possible. The radius of curvature of the bottom 
bends and also the top bends, when the bars are continued near the upper surface of the 
beams, should be about 12 times the diameter of the least side of the bar. When vertical 
reinforcements or stirrups are used to resist diagonal tension, it is usual to make them 
of the same sectional area throughout. As these bars are numerous and have to be 
bent to small curvatures so as to pass closely around the longitudinals, they should not 
exceed | in. diameter, and may well be t^ or | in. diameter, as these sizes are easier to 
bend. 

All diagonal tensile reinforcements should be securely attached to the longitudinal 
bars. This is sometimes effected by indenting the longitudinals to receive the diagonal 
tension bars and tying the two tightly together with wire ties, but the stress on the 
longitudinal bars must have become sufficiently reduced to admit of the indentations. 
It is obvious that any form of reinforcement in which the diagonal tension bars are 
rigidly attached to, or are integral with, the longitudinals is greatly to be preferred. 

In the design of T-beams it is advisable in every case to place vertical or inclined 
reinforcements throughout the whole length of the beam at distances apart not greater 
than the lever arm (a) of the couple resisting the bending moment. 

As a consequence of this provision, the value of the resistance of the concrete itself 
should only be taken into account in the design of rectangular beams. 

It is usual to allow a safe tensile working stress on diagonal tension reinforce- 
ments of only three-quarters that allowed for direct tension. Consequently for mild 
steel the limiting working stress in the steel for these reinforcements is taken as 



307 



CHARLES F. MARSH. 



[CONCBETEJ 



i^ ooo lb per ^q. in. When reinforcement is used to resist dia£,^onal tensile stress the 
resistance of the concrete nuist not be taken into account, as the concrete must hava 
cracked long before the reinforcement is stressed to 12,000 lb., although the cracks are 
unnoticeable and too fine to be detrimental. 

INCLINED OR BENT-UP BARS. 
The difference of the longitudinal tensile stress (where B, is the greater bending 
moment, at one extremity of the length Z., and B., is the lesser bending moment, at the 

other extremity of the length /.) will he^^^=^ = ^=^^ where S,„ is the mean shearing 

ci (I (^ 

force on the length h and a is the lever arm of the resisting couple. 

When the increment in the stress in the tensile reinforcement over any length 
I, is to be taken by inclined reinforcements or bent-up bars in tension and by the concrete 
of the beam in compression, one-half of this increment in the 
stress may be considered as being resisted by the concrete in 
compression on such lines as those parallel to a d and c f {Fig. 1) 
cutting the longitudinal tensile reinforcement and one-half by the 
reinforcement in tension on such lines as c b and e d {Fig. i). 
The stresses on the verticals, such as c d and e f, balancing one a 
another. . 

It is to be noted that this will not be true when the lines such riG.l- 

as a d, c b. e f, and e d have flat slopes, since in such a case the 
concrete in compression would be over stressed, and consequently we must assume that 




* Proof that B^ — B 2 =S is as follows: — 

If we consider a length of a beam to the left of the centre between a section (X) at a distance of (x) 
from the left support and a section (F) at a distance of (y) from the left support, and use the following 

symbols — 

i?j;, = reaction at left support, 
P^ = any loads to the left of section (Z), 
PFi = any loads between the sections (X)'and (F), 
(The W's and W^'s being of any intensity,) 
^ = the distances of the loads (W) from the section (A'), 
and z^ = the distances of the loads {W^) from the section (F), 
We have for the shearing force at section (.Y) — 

The mean value of the decrease of the shearing force on the length {y—x) between the sections (A') 
and (F) will be — 

iy-x) 
We have therefore for the mean value of the total shearing force on the length (y — x) between the 
sections (X) and (F)— 



vPF- 



(y-x) 



The total shearing force on the length (y—^) will therefore l)e— 

S=RjJy-x)-^ [ W{y-x) \- - ^{W,z,). 

The bending moment at section (X) will be— 

B^^-RLX-::i{Wz). 

And the bending moment at section (F) will be — 

B^^RLy--i:(Wz)-:L\ yviv-x) \ -^iw,z^), 

and the increase of the bending moment over the length (y — x) will be— 

B,-B,,-R,Jy-x)--^\ W(y-x)\-^{W,z:)^S. 

308 



y, CTON>TUUCTI<XAn 



RniNFORCIi.^JENT IN HE A MS. 



if tlu' r<'iiif()ii'<nunls on lines sik h .is (" /) .ind r d Uaw a lesser slope to the horizontal 
than soiiK' limifiii'f aiii'U- lhe\ must he oalinilaled as resistinif iiion- than one-half the 



/>\ - li., 



S,„L 



stress of '*' '*•' or *^"''\ \\'e will tiK lefoie assume thai for an-^les l<ss than 45° to 

</ ii 

tlu' In)ri/oiital the r<inforreinenls will resist a Liradiially increasin<^ j)ro[)orlion of the 
stress until an anj^lc of say 25° is reached, at which they must be assumed as resisting 
the whole of the stress. Diaj^ram Fii*,. 2 j4ives the r<'eiprorals of the proportion of the 
total str<'ss which must Iw tak<'n uj) by ih<'. inclin<'d r<'inforcem<'nts for angles b<'lw<<'n 
45° and 25° lo the liori/.ontal ; for anj^U's l<'ss than 25° the reinforcenunts must be 
assumed to take up the whole of the str<'ss. 

Since the increment of stress in the longitudinal tensile reinforcement over a length 

h is ^ '" \ we therefore get — 

a 



AstCosd = ^^Xq {See Fig. 3) 
a 
1 ^ 

Cos (^.A,t. 



/f//0 OVER 
4S 



(1) 



or <S,„ = - 

q Is 
Where A, is the sectional area of the inclined bar 

t is the safe tensile resistance of th<' steel to 

diagonal tension, is the angle of the inclined bar 

to the horizontal, and q is the proportion of the 

stress taken by the reinforcement. Where the 

reinforcement makes an angle with the horizontal 

of 45° or over has a value of 2, and for flatter 

angles it has the values given in Fig. 2. 

The horizontal projection of the bent-up or in- 
clined bar between the points where it intersects 
the axis of the tensile reinforcement and the centre 
of the compressive resistance must be equal to / j., 
and consequently when ^ = 45" /« = a 
andS,„= 2 x 0*707 A.^t = r414 A^t 
and in all cases 

Cos<^ 



(2) 




2£ 
/)ND USS 



Is = aCot 



Sin ^ 



i/^a/ues of '/<^ 






, f^ ,a.A J Cos Sin 1 , , „. 
and S,„ = J. ■ — - — = -. Ast Sm 



e (3) 



Fig I. 



q a Cos d q 

VERTICAL REINFORCEMENTS OR STIRRUPS. 

In the case of vertical reinforcements resisting 
diagonal tension we must consider the beam as 

having a web of the X-braced type {Fig. 4), with diagonals sloping 
upwards away from the support, such diagonals being under com- 
pressive stress. This bracing is replaced in the beam by the fibres 
of concrete cutting the longitudinal tensile reinforcement and parallel 
to the slope of the imaginary diagonals. 

These fibres, together with the vertical reinforcements, take up 
the increment of stress in the tensile reinforcement or 

By — B.) _ SjJs* 
a a 

The stress on the vertical reinforcements will therefore be 




See note p. 308. 



309 



REINFORCEMENT IN BEAMS. 



but 



iCQNCBETEl 




Ast= Tan^, 

a 



Is 



-^=Cot^ and :.Ad = S, 



(4) 



Fig 4. 



This stress is, of course, the same as would occur 
in the verticals of an N-braced girder, as shown by 
Figs. 5 and 6. 

If the sets of stirrups are ph\ced at equal dis- 
tances apart their sectional area must consequently 
vary in an arithmetical series of i, 3, 5, 7, 9, etc. 
It is generally desirable, however, for the sets of stirrups to be of equal sectional 

area throughout. 

It will be seen from Fig. 4 that a 

set of stirrups having a tensile 

resistance of Aj = S„, resist a 

total longitudinal tensile stress of 

Bi -Pg S,„ls. 
a a 

If, therefore, we reduce or increase 

S / 
the value of "' "' we must reduce 
a 

or increase ^.s^ in same ratio, or 

S / 
4 .si must vary as '" '" 



a 

But as Ast is to have a constant 
value if S,„ increases or decreases 

— must vary inversely as S„,. 
a 

Therefore for any value of S,„ 

. , , S,„/s where the value 

A>,t must = — ^^-^ 
a 




Fi G. 5. 




of Sm varies inversely as the value 

of ^-^ 
a 

But in any beam a will be con- 
stant, therefore aAj, = S,„ls (H) 
Where S,„ and h vary inversely 
as one another, or if we make aA^t 

constant <S„,/.s must be constant FiG. €>. 

and equal to aA^t. 

But S„,l, is the area of the shearing force diagram on the length U, Is being the pitch of 
the stirrups. 

We can ihcr<-U)U' calculaU^ th<' v.-iKh- of dAj for any b<'am and any arc^a of stirrups 
and divide up the shearing force diagram into areas <'qual to aAsf, ^"""^l ^^^^ liniitmg 
verticals of such areas will give the si)acing of the stirrups. 

Table I. gives the vahu-s of A ^1 for various diameter round and square bars with 
various numh<r^ of double hranclK's, which may b<' nuillii)lic(l by the value of a lor 
any particular Ix'am. 

If the load is uniformly distributed the slK-aring forc<' diagram for thc^ half-sj)an 
will be a triangle such i\ A, li, C, Fig. 7. Th<' value of A J for the set of stirrui)s 
selected can be obfain<'d from 'I\'ibl<- I. 

For the first set of stiirups (i.r.. those at the centre of the beam) the value of S ,„ 
must be equal to A J. 
310 



^ trasMin/rnoNAi 



N(,1NH.PIN(, 



g] 



REINFORCEMENT IN BEAMS- 











■rAiii.i': I. 












Dianu'ttT or 
side ot bar. 

:) 
in 

i 


l\(JUluls. 


Squares. 1 


for 


Resistance of s 


lirnips 


les. 


t 

for 


Resistance of stirrups 


les. 


a 

various lumibers 


of brand 


a 

various numbers of brand 


2 


4 

593 
1390 
2352 
3672 
5304 


() 


s 

1186 
2780 
4704 
7344 
10()08 


10 

1482 
3475 
5880 
9180 
13260 


2 


4 


6 


8 


10 


296 

6<)5 

1176 
1836 
2652 


889 
2085 

3528 
5508 
7956 


375 

885 

1512 

2352 

3384 


650 
1770 
3024 
4704 
6768 


1025 
2^55 
4536 
7056 
10152 


1300 
35,0 
6048 
9408 
13536 


1675 

4425 

7556 

11760 

16920 



NOTK. Tlu'si- values are calculated for a safe working tensile stress of 12,000 lbs. per sq. in. If 
any other stress is used they must be altered proi)ortionately. 

Making the value of 5 „, for the portion of the shearing force diagram at the 
apex = ^,s^ »t will be seen from Fig. 7 that the length from the centre of the span to 

the second set of stirrups = /« = 2. S„,—^ = S„, 

AB reaction at support. 

Lay off this distance Z, = CD from the centre of the span (Q and erect a perpen- 
dicular cutting the beam this will give the position of the second set of stirrups from 
the centre of the span. 

Now describe a semi-circle on AC. 

From C as centre with CD as radius describe an arc cutting the semi-circle at E^ 
draw E^E vertical cutting AC at E. 

Set off along CA distances EF FG -GH ■ HJ • etc., all equal to CE and draw 
verticals FF, GG, HH, JJ , etc., cutting the semi-circle at F, G, H, J , etc. 

With C as centre and CF, CG, CH, CJ , etc., as radii draw arcs cutting CA at G„ 
Hn L, J„ etc., verticals from F„ G„ H„ J,„ etc., will divide the triangle ABC into areas 
all equal to CDK, and these verticals produced through the beam are the positions 
where sets of stirrups are to be placed. 

If the resistance of the concrete is to be taken into consideration we must find this 
resistance and set up a vertical ordinate equal to its values on the diagram of shearing 
forces, and omit all the sets of stirrups between this ordinate and the point of no 
shear on the beam except the set nearest the ordinate. 

In the case taken for the example {Fig. 7) the span of the beam was 16 ft., the 
uniformly distributed load 4,000 lb. per foot run, the width of the beam 10 in., and 
the effective depth 24 in. The reinforcement was stressed at 16,000 lb. per sq. in., 
and the maximum stress on the concrete was 600 lb. per sq. in. The value of the lever 
arm was therefore 24 x o-88, and the resistance of the concrete of the beam to diagonal 
tension was therefore 60 x 10 x (24 x o'88)=: 12,672 lb. 

Consequently the sets of stirrups on the verticals from D and F ^^ would be omitted 
if the resistance of the concrete was taken into account. 

The following example shows a method which may be adopted in calculating the 
resistance to diagonal tension in more complicated cases, and when inclined bars are 
used as well as stirrups. 

Example. — A T-beam span 18 ft. loaded with 16,450 lb. from a column at the 
centre of the span, and also two loads 6 ft. from either support of 12,730 lb. from 
secondary beams. Thickness of slab 4 in. Beams continuing over several supports. 
Assume depth of rib to be 20 in. and width 18 in., weight = 200 lb. per lin. ft. 



c 2 



3u 



REINFORCEMENT IN BEAMS. 



iCDN CBETEl 



B = 1,207,236 in. lbs. approximately 



B 



width of flange acting with T-beam= 15 x 4 = 60 in. ^ = 21,120 giving d = 17 and 

^, = 6-72 sq. ins., or. say, 3-li: in. rods in top layer and 3-li in. rods bottom layer. 
The depth of the rib will be 17 in., weighing 180 lbs. 



The reactions at the supports are 



16,450+25,460 + 3,640 



= 22,575 lbs., and the 




c 

shearing f:ue diagram will he <is shown in Fig. 8. As the shearing force diagram is 
the same on both sid<-s of th<- c<nlre of the si)an we need only use th<> l(Tt half. 

In Fig. 8 draw the half-elevation of the Ix'am to any scale and plot the shearing 
force diagram to scale below the horizontal line intTK .iting the bottom of tlu' Ix'am. 

A sufficiently accurate approximation for the lever arm for a T-beam is (i = d- ^' 



and therefore in this case a = \7 — 2'" ^^ '^^ 
312 






REINFORCEMHNT IN BEAMS. 




'carjn<^ resistec/ Iry Oent- 
ars sAoK/n thus ■' — 



ecr/^/na res/ste(/ /;y 




FiQ 8. 



313 



REINFORCEMENT IN BEAMS. [CDNQgETE] 

If we bend up a bar of the tensile reinforcement 15 in, from the support, and others 
30 in., 45 in., 60 in., and 75 in. from the support. 

The bending moment at "/^ in. from the support will be approximately 

5(22,575 X 75 -180X6-25 X 37-5 -12.730 X 3)- |{ 1,693,125 -(42,187 + 38,190) } 

= 1,075,165 in. lbs., 

and assuming the lever arm as 15 in. the sectional area of the tensile reinforcement 

required will be 

, 1,075,165 ...„ 

At= -=4 48 sq. m. 

16,000X15 ^ 

The bending moment at 60 in. from the support will be approximately 
1(22,575 X 60 - 180 X 5 X 30) = (1,354,500 -27,000)§ = 1,327,500 X i = 885,000 

and assuming the lever arm as 15 in. the sectional area of tensile reinforcement required 

will be 

. 885,000 ^.^„^ 

At= — 3 686 sq. m. 

16,000X15 

The bending moment at ^^ in. from the support will be approximately 

1(22,575 X45-180X375X22*5) = |(1,015, 875-15, 187) = 1,000,688 Xf = 666, 125 in. lbs. 

, , 666,125 ^.„^. 

and At= = 2 775 sq. m. 

16,000X15 ^ 

The bending moment at 50 in. from the support will be approximately 

§(22,575 X 30- 180 X 2-5 X 15) = ^677,250-6,750) = §(670,500) 447,000 i.i. lbs. 

, , 447,000 ..p^ 

and At= = 7^2 sq. m. 

16,000X15 ^ 

The bending moment at 75 in. from the support will be approximately 

§(22,575 X 15-180X1-25 x 0-625) = §(336,938) = 224,625 in. lbs. 

, , 224,625 ^.^.^ 

and At — = 933 sq. m. 

16,000X15 ^ 

If we bend up i — ig-in. rod at 75 in. from the support, i — ig at 60 in., i — ig at 
45 in., i^ — I J at 30 in., and i — 15 at 15 in. from the support we have 

5*665 sq. in. tensile reinforcement at 75 in. from the support, one outer ig-in. 

rod being bent up. 
4*667 sq. in. at 60 in. from the support, the central ig-in. rod being bent up. 
3*669 sq. in. at 45 in. from the support, the other outer ig-in. rod being bent up. 
2*442 sq. in. at 30 in. from the support, one outer i^-in. rod being bent up. 
1*215 sq. in. at 15 in. from the support, the other outer 15-in. rod being bent up. 
These areas will give ample resistance in all cases. The rods will be bent up at 
angles of 45°, special care being taken to form tJic bends with flat curves, in order that 
the compression on the concrete at the bends may be reduced as 7}}ucJi as possible. The 
radius of curvature for the bottom bends and top bends, if the bars are to be cotitinued 
near the surface of the beams, should be about twelve times the diameter of tJie bar. 

The sectional area of i ly-in. rod is ()'994 sq. in. and that of i- i:l-in. rod is 
1*227 ^Q- ^"• 

And as the distance ai)art of the b<nt-uj) rods has been mad<' equal to the lever arm 
we have from equation (2) the shearing force resisted by <'ach of the la-in. rods 

<S„, = 1-41 4X12,000X0-994 = 16,866 lbs. 
and the shearing forces resisted by each of the i:J^-in. rods 

S„, = 1*414 X 1 2,000 X 1*227 = 20,720 lbs. 

3H 



[^^NE ^'iK?^^J /^/i/NFO/^C/iA/yiAfr IN BHAMS. 

Now draw :\ luirizont.il litK on the sho.nin^ forot' di.'ij:jram .it a dislancc below the 
bottiMii of the beam of -.m),7jo lb. to ibc scaU- of loads and for a distance of 2^ ft. from 
tbi' support, and anotlu r borizontai line at a diNlanrc of ir),S6b lb. to the scale of loads 
from 2I fl. to <>.', fl. fioni ibe siipixut. Tbe area of lb<' siuarinj^ force diaj^rani enclosed 
by tlw'se lines indiial<s ibe slK'ar r<-sist»d b\ tbe bent-up bars, and the j)(M-tion not 
enclosed indicates tbe slu ar reniaininj^ and which must be resisted by further rein- 
forc<'ments. These portions of the shear will Ix' taken by vertical stirrups, and as 
diai^onal tension i rinforcements must be placed throuf^hout the entire sjjan at no greater 
distance apart than tbe len<;th of the lever arm, the sj)acinj4 of the stirrups must not 
cxceeil this Uiii^th on lh<' portion l)etwe<'n the section b] ft. from the support and the 
centr<' of the si)an. 

Now if we use -A-in. diameter bars for the stirrups, each stirru]) having two 
branch<>s, from Table 1., and with a value of 0=15 wc g<'t 

lor two branches <r^,i =^ 1,836 X 15 =27,540 lbs. 
,, four „ rr^,^ = 3,672x 15 = 55,080 „ 

„ six „ rr^.si = 5.508 X 15 = 82,620 „ 

The mean shearing force on the remaining portion of the shearing force diagram 
for a distance of 2^ ft. from the support as scaled is 1,600 lb., and the area of this 
portion of the diagram is therefore 1,600x30 = 48,000 lb. 

\V<' must therefore insert two stirrups at a distance of 2^ ft, from the support. 

By trial and error we find that portion of the diagram between 2^ ft. and 3 ft. 10 in. 
from the suj)port =81,760 lb. 

Three stirrups will therefore be placed 3 ft. 10 in. from the support. Similarly the 
area of the portion of the diagram between 3 ft. 10 in. and 5 ft. 3 in. from the sup- 
port =8 1,940 lb. 

Three stirrups will therefore be placed 5 ft. 3 in. from the supports. 

The central ordinate. of the remaining portion of the diagram up to the load of 
12,730 lb. at 6 ft. from the supports is 4,630. The area therefore is 4,630x9 = 41,670 lb. 

The remaining shear to be resisted "by the three stirrups will be 82,080 — 41,670 = 
40,410 lb. 

The shear between 6 ft. from the supports and the section 65 ft. from the support 
where the first bar is bent up is resisted by the bent-up bar, therefore an area of the 
shearing force diagram of 40,410 is required between a section 65 ft. from the support 
and the centre of the span. 

The area of the portion between 6\ ft. and 6 ft. 7^ in. from the support is 38,8801b 

Three stirrups will therefore be placed 6 ft. 7^ in. from the support. 

The area of the portion of the diagram between 6 ft. 7^ in. and 7 ft. 5 in. from the 
support = 8i,5io lb. 

Three stirrups will be placed 7 ft. 5 in. from the support. 

The area of the portion of the diagram between 7 ft. 5 in. and 8 ft. 2^ in. from the 
support = 80,085 lb. 

Three stirrups will be placed 8 ft. 2^ in. from the support. 

A further three stirrups will be placed at the centre of the span. 



315 



REINFORCED CONCRETE VIADUCT. 



toNCRETEl 




REINFORCED CONCRETE 

VIADUCT, MARTIN'S 

CREEK, U.S.A. 



The following particulars and illustrations of this 'viaduct noio nearing completion 
ha've been taken from the ** Engineering Record,"— ED, 



Xext to the 7\inkh:inn()ck viaduct the Martni's Creek viaduct is the most im- 
portant structure in the 40-mile relocation of the main line tracks of the Dela- 
ware, Lackawanna and Western Railroad between Clark Summit and Halstead, 
Pa. It is built entirely of concrete, with long- and lofty spans on deep 
foundations, carried to solid rock through beds of clay and boulders. 

General Description. — The viaduct is a three-tack structure, 1,611 ft. 8 in. 
long and 150 ft. high above the creek. It will be 48 ft. 4 in. wide over all at 
the arch rings, and will have two full-centred spans of 50 ft., two of too ft., and 
seven three-centred spans of 150 ft., with a rise of 59 ft. 

Kach span will have two arch ribs 12 ft. apart in the clear. For the 150-ft. 
spans these ribs will have a width of 17 J ft. and a thickness at the crown of 
6 ft. and will each contain 1,000 vds. of i : 3 : 5 concrete. They will carry solid 
transverse spandrel walls 12J ft. apart supporting floor arches and parapet walls. 
The west end span is made of two-arch ring segments of loo-ft. span, forming 
an abutment. The concrete floor system is carried to the centre or crown of 
the abutment arch, with the adjacent fill extending to the end of the floor; 
the toe of the slope extends to the centre of the westerly 150-ft. span, the 
lOo-ft. arch being entirely covered by the embankment. The east half of the 
westerly loo-ft. span carrying the bridge floor is enclosed on both sides, with 
spandrel walls reaching to the surface of the slope and giving the appearance 
of a solid masonry abutment. At thi- land vnd of this span the tracks are laid 
on tlu; f)]]. 

The c(jmpleted slrucluie will (^ontain about 84,000 yds. of concrete and 
w ill involve about 25,000 yds. of foundation excavation. 

Delivery of Materials. — Work was commenced in June, 191 2, and a side 
track for material was connec^led with the main line. An additional track was 
also l>ui]l parallel lo the side liick, j)arlly supported on a wooden trestle, to 
provide lor receiving, unloading, and storing cars. I^'rom 400 to 500 cars of 
material are received mc^nthly, and about 8,000 yds. of broken stone, 4,000 yds. 
of sand, and 4,000 barrels of ci-ment are kept in storage. Sand and stone are 
dumped into lu-aps on llie sid'-iiill and are llience delivered by a Mead-Morrison 
chimshell bucket lo storage liopjx-rs at the concri'te-mixing j)l;inl. At the 
mixing plan! a 2-yd. Carlin ci!l)i("d mixer is mounted about 10 ft. above the 

316 



[f\ t N( il N M W 1 N< t ^ — ^J 



REINFORCED CONCRETE VIADUCT. 



'>''*"l^- l"i»>in 11 ((Miciclc is (iiscli.'ii^cd Inlo l)U(I«'l.s .-md delivered over the 
service Uacks to tlic work. 




31 



REINFORCED CONCRETE VIADUCT. ICQNCBETEl 



Concrete is distributed to the pier sites by a 3-ft. gauge surface track which 
runs the full length of the viaduct and serves the power plant, shops and storage 
vards. There are in all eight switches, all of which are visible at a central 
point, where they are operated from an interlocking stand by one man, thus 
effecting a considerable saving of time and increasing the safety. 

Sawniill. — An important part of the plant is the sawmill, equipped with 
a ripsaw, handsaw, cut-oft' saw, planing mill, and moulding machine, all 
operated by one 25-h.p. and one 15-h.p, engine. Besides cutting and planing 
timber and doing miscellaneous work, the sawmill is of great importance in 
sawing the heavy timber into boards. For this contract a large amount of 
i2-in. by 12-in. yellow-pine timber was ordered, and most of it was first used 
for the construction of towers, trestles, and for the heavy bracing in the deep 
foundation pits. As fast as released the timber is sawed up into smaller sizes 
and boards and is planed for use in the construction of concrete forms. 

Pier Foundations. — About 30,000 yds. of earth were excavated at and near 
the pier site by a Marion steam shovel, which made a cut with an average 
depth of about 20 ft. parallel to the axis of the viaduct. The spoil was used 
to form embankments for the service tracks and to make a fill, on which the 
machine shop and concrete plants were located. The soil consists chiefly of 
compact water-bearing sand containing many small boulders and considerable 
gravel, and overlies hard blue flagstone at a depth of from 18 to 70 ft. below 
the surface. 

The pier foundations were excavated to sound rock in open cofferdams 
made by driving one or two tiers of steel sheet piling with a No. 2 Vulcan 
steam hammer operated in 40-ft. leads suspended from a derrick boom. Where 
two tiers of sheeting were required the inner tier was driven first and the 
outer tier was driven afterward at a 5-ft. distance in order to allow clearance 
for excavating the earth between them. 

Siiceting, Draining and Concreting. — About $10,000 worth of steel 
sheeting was required for the work, and some of it has been pulled and 
redriven four or five times, and endures the service so well that about 80 per 
cent, of it will eventually be salvaged. The sheeting was driven with care, 
and when a pile encountered serious obstruction by a boulder, driving on it was 
suspended and adjacent piles were driven down beyond the boulder and excava- 
tion made to undermine and move the boulder, or in some cases it was blasted 
and removed so that the piles could be driven without further trouble. By this 
scheme the sheeting was put down with very little battering. 

Although water was encountered, no difficulty was experienced In keeping 
the foundations dry by the use of 6 and 8-in. centrlfug-al pumps. Most of the 
excavati(jn was done by a li-yd. Williams l)U(kel suspended from a derrick 
boom. The sheet piles were covered uitli tar paper to prevent adhesion of 
concrete, anrl the cofferdams were filled nearly lo the surface of the ground with 
concrete deposited against the ste<.:l sheeting without ihe use of forms. After 
the concrete had set \hv. shut piles were pulled in sets of one, two or three by 
an eight-part tackle suspended from an A-frame and by a whip line led direct 
from the derrick bfX)m to the hc/lsllng- engine. 

Pier Construction. — Above the surrae<' of the ground the pier concrete was 

318 






REINFORCED CONCRETE VIADUCT. 

ilh 



„,,,,., ,„ „,„„,.„ for.ns ,ra<l. of brgo ,m.h1s ,7 L- '. -- h,«h, Iuum, w, n 
';.„., ,,.„,. \n-,- fou, ,-!.. .o.„-s<.s ..f .-..n.-,-,.,.. lK,.l l..-n .l.-pos,,.! ,n ,hc 
': , n.l U». l.M >n,„... l,..l M-l scv,.K,l .Inys, .1,,. p.n.ls w.-r.. .„s,„m„,.. ,-d. 




were hoisted i6 ft. by the derrick and reassembled in position for concreting 
above, and so on. Concrete was distributed to the piers in three-car trains, 
each taking two full buckets, with room to receive a third empty bucket. 

Pier concrete was laid during the coldest winter weather, care being taken 

3^9 



REINFORCED CONCRETE VIADUCT. [CQNCBETE] 



to heat the water and the piles of sand and stone and to keep the forms warmed 
l)y steampipes under protecting tarpauHns. The maximum amount of concrete 
deposited in one month was 8,500 yds., working- one ten-hour shift daily. 
About 6,000 yds. of this concrete were deposited in forms ; the average haul 
Avas 800 ft. 

The concrete for each pier was handled by a g-uyed-derrick with a boom 
from 80 to go ft. long- operated by a Mead-Morrison three-drum hoisting engine, 
of which sixteen arc installed on the work, one for each derrick on the viaduct 
and three at the concrete plant. The derricks were at first set up on the surface 
of the ground or on timber towers at the pier site, and after the completion of 
the piers up to the top of the extensioins for the arch ribs the derricks placed a 
g-inpole on top of the pier and the latter lifted first the derrick masts and then 
the derrick boom to new position on top of the pier. The derrick then removed 
the ginpole and was ifl readiness to erect the steel truss centres for the concrete 
arches and to lay concrete upon them. 

Arch Construction. — The i5o-ft.-span arch ribs are built on steel truss 
centres. The smaller spans have wooden centres. Four steel centres, each 
having- five ribs or trusses, have been provided and erected on the piers in 
readiness for the construction of one rib of each of four consecutive spans. 
After these ribs are completed and the concrete sufficiently set the centres will 
be struck and the sets of trusses will be moved as units 29^ ft. transverse to the 
axis of the bridg-e into the centre line of the other ribs which will be built on 
them, after which the centres will ag-ain be struck, the trusses they temporarily 
supported from the finished ribs separated into four pieces each, lowered to the 
g-round by tackles suspended in the clearance between ribs, transferred to 
adjacent spans, re-erected, and so on until the spans are all completed. 

After the concrete has set thirty days the centres are struck by means of 
the adjustable members in the crown panels of the trusses. Part of the concrete 
for the arch ring-s will be handled by the pier derricks. As these cannot reach 
U) complete the spandrel walls and floor arches in the centres of the spans, it 
is probable that they will be supplemented by a cableway. Both ribs of each 
loo-ft. span are simultaneously concreted on centreing formed of timber trusses, 
with horizontal bottom chords supported on the umbrella projections from the 
piers and on a pair of eight-post framed centre towers. 

Steel Arch Truss Centres. — The trusses, which weigh about 28 tons each, 
are erected four pieces each by the derricks on the piers. The end pieces are 
pin-conne(Med to the steel g-rillages on the pier copings 11 ft. below the springing 
line, and are held in position by anchorage boils passing through the tops of 
the concrete umbrella se{ni()ns and })y anchor bolts at the foot of trusses. They 
are self-sustaining until the (^rown sections are in turn hoisted by the derricks 
and bolted to them and ihe centre pins driven, niaking them self-suppt)rting. 
\n each set there are five trusses spaced 3 ft. () in. apart and braced together 
with sway frames and lop-and-boltoin lateral X-bracing with bolted c-onnections. 

The trusses arc coven^d with lagging, ol which the upjjer surface is dressed 
smooth and grea.sed. Bulkheads are built on the sides and j)arallel to the axis 
of the arch to divide the ring into sections corresponding to voussoirs. These 
are concreted in pairs synnnetrically j)laced on ()j)i)()site sides of the centre, the 

3:0 



r,.coNMmK-..oNAi. ] RHINFORCHD CONCRETE VIADUCT. 

ffv^N^■lN^-^ yiNii — | 

w,.ik l.cin- tlunc in the m(|Iuiuc indicated by the niini<r;ds on the aee()nii)anyin^ 

tlia-iam, so as to maintain hahnv vd loachn-s on llie centreing-. After adjacenl 




voussoirs are cast, the bulkheads between them are removed and the narrow 
portions of arch ring- between them are concreted, forming keys which lock, 
them together. 

321 



REINFORCED CONCRETE VIADUCT. [CONCCETEl 

The desig-n and construction of the viaduct are under the direction of the 
engineering- department of the Delaware, Lackawanna and Western Railroad 
Company, of which Mr. G. J. Ray is chief engineer, Mr. F. L. Wheaton 
engineer of construction for the Martin's Creek cut-oit line, Mr. A. B. Cohen 
concrete engineer, and Mr, Walter Lozier resident engineer in charge of the 
viaduct. The contract for the viaduct was awarded to the F. M. Talbot 
Company, of New '^'ork City. 



3Z2 



J CONMPIK'IION'AI 
V l.NdlM-liflNt. ^ 



ELECrROI.VSIS IN CONOR llTh. 




ELECTROLYSIS IN 
CONCRETE. 



Report by E. B. ROSA. BURTON 
McCOLLUM and O. S. PETEKS. 
ol the U.S. Bureau of Standards 




The question of Electrolysis in Concrete continually gi^ves rise to discussion, dnj 
therefore the folloivinci short resume of some experiments recently carried out by the 
U.S. Bureau of Standards may not be ivithout interest.— HD. 



l^RKVious work on ih^ danger lo reinforced concrete structures due to elect r<jly sis 
l)y stray electric currents has given somewhat contradictory resuUs as regards 
llie extent and nature of the possible damage. The question has now been 
re-investigated by the Bureau of Standards, and the principal results may be 
summarised here. 

The experiments were made with cylinders of i : 2| : 4 concrete, 6 inches 
in diameter and 8 inches long. The specimens were kept in wet sand for 20 
days before use. One electrode was an iron rod, embedded along the axis of 
the cylinder; the other was a sheet-iron cylinder, placed in a vessel of water 
surrounding the test specimen. The central rod could be made anode or cathode 
at will, and the external electro-motive force could be varied within wide limits. 

With a high initial potential difference, such as 57 volts, the central rod 
being the anode, there was at first a rapid rise of temperature, followed by a 
fall, due to an increase of the electrical resistance. The concrete was soon 
cracked, and then broke into several pieces. The damage was due entirely to 
rusting of the reinforcing rod, causing expansion. There was no disintegration 
of the concrete itself, as each broken piece was found to have its original 
strength. 

With potential differences of 15 volts or less, cracking did not occur, and 
with concrete made from normal Portland cements there was practically no 
injury, although the total number of ampere hours passed through the specimens 
was actually larger than in the high voltage experiments. It therefore appears 
that damage due to oxidation at the anode is not likely to occur unless the 
leakage of current is abnormally high, and this danger is not a serious one. The 
coating of the reinforcement with copper or aluminium has been proposed, but 
is of no value, as both of these metals disintegrate readily in contact with 
concrete when a current is passed. The bursting pressure exerted by the iron 
in rusting was measured, and was found to be as high as 4,700 lb. per square 
inch. Even with high potential differences, corrosion was not found to take 
place when the temperature was kept low by artificial cooling. The addition of 
salt to the concrete increased the corrosion very greatly, owing to the increase 
of conductivity and to the destruction of the passivity of the iron. 

Contrary to previous obser^■ations, the concrete was observed to soften 
considerably in the neighbourhood of the reinforcing rod when the latter was 

323 



ELECTROLYSIS /.V CONCRETE. {OCJNCKCTEJ 

„K,de the cathode. The softening action began at the metal suriace attd sptead 
outwards. The softened material regained its hardness on exposure to 
but remained brittle and friable. This action proved to be of greater pracucal 
i, ;-tance than the corrosion at the a.tode, as it was foun to <;--■ y^ - 
well as with high voltages, the action being roughly P^P-''^-^ '"^f^^^Jf ^^^^^^ 
of potential. The effect has been traced to the presence of alkah salts in tne 
concr «. These salts undergo electrolysis, resulting in the formation of ulkaU 
hvdroxide near to the cathode metal. At a short distance rom the cathode no 
injurv' to the concrete could be observed. Any increase of alkah salts accelerated 

'"^ oZ ;:L:ti::a-consequence of this series of experiments is that the sug- 
gestion which has been made to protect reinforced concrete buildmgs by apply- 
fng an external electro-motive force, making the reinforcement the cathode, 
is worse than useless, as this would result in an acceleration of tne d.s.ntegratmg 



action 



Waterproofing agents were not found to have any marked effect in checktng 
electrolvsis It appeared likely, but was not proved, that external waterproof 
coatings would be more effective than waterproofing agents used m Ae m'>^"-8: 
of the concrete. Painting the reinforcement was of no advantage, and had the 
defect of lessening the bond between metal and concrete. 

I precautions in actual practice, the authors make the foUown^g recont- 
mendations :--All direct current circuits within a reinforced concrete btuldmg 
should be kept free from earths, and tests should be made front t,me to tm 
with earth detectors. Lead-covered cables should also ^e >-" a'ed The 

jreneral earthing of metallic conduits is not to be recommended, and although 
ft is advisable to connect all the metal work of a building together as far as 
practicable, the connected metal should not be earthed. . 

The report contains a large number of quant.talive delerm.nat.ons of 
resistance, etc., under various conditions. 



3*4 



\», CTONMPUrnONA 1 1 



REINFORCED CONCRETE v. CAST IRON. 









REINFORCED CONCRETE 

versus CAST IRON FOR 

LIGHTHOUSE CONSTRUCTION. 

By C. WESEMANN, Civil Engineer. 

From exjimples pre'viously given in our journal, it has been found thai reinforced 
concrete can be used advantageously for lighthouse construction, and although' there may be 
indi'Vidual instances ivhere a different method is vreferable for one reason or another, 
it ivould appear that great economy can be effected by the use of reinforced concrete.— ED. 



An adequate comparison between two different forms of construction for light- 
houses is almost imjx^ssible, owing to the varying- conditions and kjcal circum- 
stances which attend this particular class of building. 

Some interesting facts may, however, be ascertained by comparing the 
construction of a Dutch lighthouse erected some time ago in reinforced concrete 
and some newly built German lighthouses in cast iron. As regards site, size, 
transport of materials and available labour, the conditions in both cases were 
somewhat similar. 

The question naturally arises as to how reinforced concrete compares with 
other systems of construction adopted hitherto for lighthouses, when it is a 
question only of light structures, as against so-called " heavy-weight " struc- 
tures, exposed to the force of the sea waves. 

It is proposed, in the first instance, to give some data regarding the general 
dimensions and constructional particulars of the Dutch lighthouse — a reinforced 
concrete structure — which was erected on the island of Goerree-Flakkee, near 
the village of Ouddorp, in Holland. (See Fig. i.) 

The building is situated on the top of one of those dunes so typical of 
the Dutch coast line. Owing to the peculiar nature of the dune sand, a rela- 
tively shallow foundation is permissible, providing always that the necessary 
precautions are taken to prevent the sand from being scooped out from below 
the foundation slab. 

The height of the building, measuring from the top of dune to the platform, 
is 141 ft. The form of construction adopted is that of a cavity wall. The width 
of the outer shell at the base of the superstructure is 25 ft. ; the corresponding 
width at the top is 12 ft. 6 in. The outline of the inverted cooe is battered 
approximately i in 20. 

The cross section of the concentric outer and inner walls is octagonal in 
shape. The two walls are interlaced and tied together at each floor level by 
means of girders arranged wheel shape on plan so as to form a monolithic 
structure. 

The outer wall is strengthened at the corners of the octagon by means of 
eight buttresses; this wall extends to the full height of the tower, and this is 

" 325 



C. WESEMANN. 



[CQNCBETFJ 




FifJ. 1. Section. 
Rkinforckd Concrktk Lighthouse. 



I'i(4. 2. Sectional Elevation. 
LioHTHOusK or Cast Iron. 



326 



J, CTONM PMCriCINAl-i 
«V F-NdlNhl PlNti^ — ^.| 



RIiINFORCED CONCRHTE v. CAST IRON. 







br.icvd 1)\ hoi i/.)iil.il i^irdcrs r\Un(lini4 round \hv oclii^on. 'llii- inner wall 

whilst loiinini^ pari of ihc consl rud ion also serves as the slaii-casc well. 

Allhoiij^h ihis arranL;enicnl intrrfcres somewhat with ihe size of the rooms, ete., 
it is not parlicularlv d<-t limental in this ease, as the areommodation re(|uired 

loi' maehinei'}' ecjuip- 
menl , slorag'e, a n d 
dwelling purposes is 
very simple. The light- 
house in this inslancx* 
merely serves as a 
heaeon, and the lighl- 
house-keepers li\'e in 
adjacent dwelling- 
houses. 

The writer is of 
opinion that, in plan- 
n i n g and designing 
future lighthouses in 
reinforced concrete, the 
inner wall might be dis- 
pensed with and the 
material thus saved 
could be employed in 
strengthening the outer 
w all. A mezzanine 
tloor might be con- 
structed between two 
floors so as to reduce 
the height of the stories. 
The stairs could 
easily wind along the 
internal surface of the 
wall and be separated 
from the remainder of 
the building by a par- 
tition wall. A light- 
house constructed on 
these lines would be 
very similar to the one 
in cast iron illustrated 
in Fig. 5. 

The cast-iron light- 
house illustrated in Fig. 5 is situated on a clayey " flat " outside the sea 
dvke, on ground which is rather soft and wet, and is covered with water by 
high spring tides. Before the actual building operations were proceeded 
with, a platform of solid clay was made in the form of a sea dyke. This 
platform carries the tower and two adjacent dwelling-houses for the lighthouse- 
keepers. 327 
n 2 




IS. 3 



View showing Reinforced Concrete Lighthouse in course of construction 
Lighthouse at Goerree-Flakkee. 



C. WESEMAXN. KONCCET Ei 

The building- rests on hig-h wooden piling, which was carried down to the 
bearing stratum. The height of the lighthouse is 112 ft. The width of the 
superstructure at the base is 25 ft. 4 in. and at the top 3 ft. 10 in. The outline 
is battered approximately i in 15. 

The wall of the superstructure consists of cast-iron plates with horizontal 
and vertically planed flanges, bolted together in sections. The wheel-shaped 
girder grillage of steel rests loose on a special bearing flange around the inside 
circumference of the wall. The groove between the wall and the outer girdle 
of the iron grating is filled in with asphalt in order to allow of partial movement 
and to ensure a plastic joint. A special staircase well has been arranged along 
the inside wall of the inverted cone. 

The internal surface of the cast-iron wall has been lined by a plaster 
insulating wall with an air space between. 

The mean thickness of the cast iron is 22, mm. — viz., 26 mm. at base and 
20 mm. at the top. A reinforced-concrete superstructure having the same 
average strength would measure about the same in centimetres. 

The proportional quantities of the two respective building materials are 
1:10, and the proportional weights (on the basis of the specific weights '/'2 and 
2'i) are, approximately, i : 3. 

The lighter weight of the superstructure naturally admits of a lighter 
foundation, but the proportion is smaller than 1:3, as the massive and heavy 
substructure of the ground floor is common to both forms of construction. 

In comparing- the two methods of buildingf, the following- are perhaps the 
most important points to bear in mind : 

Where a site is a difficult one, a minimum amount of building material and 
lighter foundations may be a consideration. 

Then, again, reinforced concrete requires a somewhat complicated and 
diflicult scaffolding, which, when exposed to the rough sea weather, is very 
liable to damage. The cast-iron structure is easily put together by means of a 
simple hoisting plant without running much risk from weather conditions; 
and, also, the main portioin of the w<jrk is carried out in the workshop. There 
are also instances where the lighter cast-iron structure might be preferable 
from the statical point of \iew, as, for instance, in earthquake districts. 

In the example here under review, however, reinforced concrete has cer- 
tainly j)rov<-(i to be the superior form of construction as reg'ards cost imd 
maintenance charges. 

The cost of erecting the Dulch lighthouse in reinforced concrete, exclusive 
of equipm(*n1, was ;^.3,55,o. 'Jhis sauK; building would have cost ;£!!"5,500 if 
constructed in cast iron, in a(X'ordan(x* with Figs. 2, 4 and 5. This shows a 
clear saving of one-third. 

These figures only a])pl\- 1f> this individual instant^e, but the question of 
cost is, of cc;urse, an import anl laclor. In other cases the above saving might 
work out somewhat higher, or, in some cases, less, according to local 
conditions. 

Figs. 2 and 4 sho\^ an insIaiKc where cast iron was used in preference to 
reinforced concrete. I lie HljIiI Ih'Um sl.inds on a saindy " flat " in the middle of 
the Jade estuary near the naval station of \\'ilhelmsha\'en. The site is 

328 



(i 






REINFORCED CONCRETE v. CAST IRON. 



Blmplitie 




Caisson. 



Fig. 4. Section. 

Lighthouse at Wilhelmshaven. 



329 



C. WESBMANN. 



icqncbetf: 



moderately exposed, and becomes dry during three hours at every ordinary tide, 
the rise and fall of which is ii ft. 6 in. The tower height from sea level 
(ordinar)- high water) to the main focal plane is 30 m., or 98^ ft. 





'ihe ffnindation consists of a circular caisson, which has been provided with 
a permanent uaterliglil hoi torn in iciiilorccd concrete. The caisson was fitted 
up and construct(;d uilli its reinforced concrete l)ottom in a dry do<-k on a plat- 
f<^)rm whicli had Ix-en specially prepared to ensure an absolutely le\cl bottom 

330 



tVtlNCilNh-WlNtt — 



REINFORCHD CONCRETE v. CAST IRON. 



{acv. Vhv caisson \\:is thru lln;itt(l into position and sunk down U|)i)n the piling, 
llu- tt)i)s of tlic wooden lilies wrrc splurically sliapt-d, so as to admit of llic 
caisson rcstinj^ upon an al)solutcly li\i'l base. 'Ilic suhst ru( 1 urc was tlun huilt 
up in inasoin\, in tlic dr\ , and faced with Dulcli c'linkcrs. Hrusli mattress work 
lias been jjhiced around llic fountkition as a ])r()t<-cti()n aj^ainst scouring'. 

VUv lii^btliousc is litted witli a doubk- set of \2 li.p. Diisel engines, electric 
Ikish lii^hts and central 
heatinj;-. Vhv usual ac- 
ct)mm()dation for dwelling 
purposes and storage of 
fuel, cooliui^ water (fresh 
water), coal, provisions, 
etc., has been provided lor. 

The cost of this light- 
house, complete, including 
designs, and supervision of 
the building, amounted to 
;£,'9,ooo ; ;£^3,ooo of this was 
devoted to machinery and 
other equipment. 

Fig. 6 shows the 
machinery equipment of the 
two lighthouses. 

A few words should be 
added regarding the archi- 
tectural aspects of the case. 

In this article, light- 
houses have been dealt with 
which were constructed in 
the shape of an inverted 
cone and with a straight 
outline, somew'hat resem- 
bling a chimney of wide 
circumference. 

If the contour line 
were arched inwards, with 
breaking points in the level 
of the floors, the building would present a better and more pleasing appearance. 

The author is indebted for the drawing of illustration {Fig. i) to the Dutch 
engineers in charge of the supervision of the building, whilst the remaining 
photographs shown and the details as to prices, etc., are taken from the writer's 
own personal experience. 




Fie;. 6. Interior View. 
Machinery Equipment. 



331 



REINFORCED CONCRETE BUILDING IN BRAZIL. [CQNCKETEJ 
O _ O O 



if|iTrftri 

~ illi i i i 





i fiff 



^|! 



REINFORCED 

CONCRETE 

BUILDING AT 

PARA, BRAZIL. 



Reinforced concrete is 
being used to a great extent 
on the neiv structures in 
course of erection in South 
America. This form of 
construction is admirably 
suited to the conditions 
pre'vailing in that country, 
and ive gi%>e beloiv an ex- 
ample of a large building 
erected there recently. -ED, 



The building illustrated by tlie accompanying- photographs and plans has 
recently been completed by the Para Construction Company, Ltd., for the 
Administration Offices of the Port of Para. 




View of Iiit<;riial t oiirt, 

Ki:INI ORCKI) CtjNCKKTE Bl ILDING AT PARA, BRAZIL. 

The entire work, excepting the walls, was constructed on the Coignet 
system of rein forced^ concrete. 

The office accommofhilion is disposed around an internal court and the 
principal over-all dimensions of the building are 134 ft. long by 81 ft. wide. 

332 



k'Sri'ihiiiK'^^l Rf'^^^t^(^F^CED CONCRETE BUILDING IN BRAZIL. 



A-m 




ca 






y ° 



fc n 



c 


23 


p 


, 


o 




u 


H 


O 


a 






k 


y 


O 










U 


r- 


a 


(fl 


Ui 




( 1 


CI. 


a 



333 



REINFORCED CONCRETE BUILDING IN BRAZIL. [CONCRETE 




The heig-ht is 52 ft. to 
the top of the flat 
roof, and from the 
foundation to the top 
of the domes is ap- 
proximately 70 ft. 
The internal court 
measures 86 ft. long- 
by 34 ft. wide. 

The building- was 

erected on reinforced 

concrete piles of about 

14 in. diameter, and 

30 ft. long, and 

arranged in groups of 

two, three and four 

connected together by 

N means of reinforced 

m concrete caps and 

2 beams. The piles 

o Oh were made on the site 

•2 < and were driven 

§ 5 through sand and mud 

•| ^ to hard ground by 

< „ means of a steam pile- 

.2 g driver. 

^ I As shown in the 

§ Q accompanying 



w 



building- 



plans, 

is coni- 

a ground 



^ ^ the 

^ posed of 

^ floor, first and second 
floors and a flat roof, 
and cantilevered bal- 
conies 7 ft. wide are 
carried around the in- 
ternal court to give 
access to all the 
rooms. The total 
area of floors, flat 
roof and balconies 
amounts to a 1) o u t 
38,000 sq. ft. 

T li V reinforce- 
ment for the pillars, 
beams, floors, and other 
parts of the reinforced 
concrete construction 
w a s c o m |) o s ed 



334 



y,cr>NMm)c-iioNAi l RBINFORCFiD CONCRETE BUILDING IN BRAZIL. 



of round slrcl hais. I lu'sc l)ars, tlu' ((imnt, tin- ^lanitc tliips, aiul a certain 
ainoiint ol liinlxr wcic tlu' onK malt rials uliuli liad to he sent lr')p.i luij^land 
lor llu' crt'it ion ol tlu- work. 

As shown in ihc accoinpanx inj; plans, \hv ]iillars were (■omj)os< (1 of a <( rlain 
nuinhiT ol lonj^itudinai i)ars of small diamcliT hound lo^cliuT hy means of 
a si)iral wire. 1 lu' l)eams were formed l)y a certain numher of straight l)ars 
in tile lowcM" and npjier portions of the heam ("onnected to^'-ether hy means of 
wire stirrups, and the slahs were composed hy means of a meshwork ol small 
hars. 

This is another exam])le of the (M)nsideral)le advantages offered i)\ the use 




i 

^ 


J 

J 
1 



View of Entrance Hall and Staircase. 
Reinforced Concrete Building at Para, Brazil. 

of reinforced concrete for work in the Colonies, or in distant countries where 
che labour of bending- the bars and putting- them tog-ether must be done by 
natives. 

It is interesting- to point out that the steel frames of the columns and beams 
in the method here employed are all made in advance on the ground level and 
hoisted into position in the moulds ready for the concreting- operation. As all 
the bars are rigidly connected and tied together no displacement of any member 
is possible whilst the concrete is being- rammed in position, and this of course 
simplifies considerably the supervision of the work. 

The walls of the building are carried by the reinforced concrete framework, 



335 



REINFORCED CONCRETE BUILDING IN BRAZIL. 



ICa^c HETE l 



the framework of each floor supporting- its corresponding load of walls, and the 
walls are formed of hollow concrete blocks moulded in advance of the work by 
a special machine. The three domes were constructed of timber and covered 
with copper. 




The building- was erected by iMcssrs. W. Cowlin and Sons, contractors, of 
Bristol, entirely by native labour under the supervision of a few Europeans. 
The architectural plans were prepared by Mr. E. M. 1\ lusher, architect, of 

33^ 



ItV EN(.lNKKklN(i->-^, 



RIiINFORCIiI) CONCRHTE BUILDING IN BRAZIL. 




^^^^^ ^ <M ------'^,^^>W^ 



337 



REINFORCED CONCRETE BUILDING IN BRAZIL. [CQNCBETE] 



London, and the whole of the work was carried out under the instructions and 
control of Mr. J. \V. Kitchin, engineer of the Para Construction Co., while the 




■. 



detailed plans and uorkiiij^ drawings for the; reinforcx-d concrete work were 
designed and j)r(r{)arcd by Messrs. iuhnond Coignet, iJd., of 20, Victoria 
Street, Westminster. 



33« 






FORMS FOR CONCRHTIi WORK. 




wnnm 



T-TT 



RECENT VIEWS ON 
CONCRETE AND REIN- 
FORCED CONCRETE./, 

Mi 

THE CONCRETE INSTITUTE, 




// is our intention to publish the Papers and Discussions presented before Technical 
Societies on matters relating to Concrete and Reinforced Concrete in a concise form, and 
in such a manner as to be easily a'vailable for reference purposes. 

The method toe are adopting, of di'viding the subjects into sections, is, ive believe, a 
netu departure, — ED. 

THE CONCRETE INSTITUTE. 

FORMS FOR CONCRETE WORK. 

By ALLAN GRAHAM. A.R.I.B.A., M.C.L 

Tlie foUoiving is an Abstract of a Paper read before the Concrete Institute at their 

forty-eighth ordinary general meeting. The Paper was illustrated by numerous 

lantern slides, and was also accompanied by a large nutnber of interesting plates. A 

sJiort report of the discussion which followed is also given. 

It has been recently stated, with some truth, that we do not often hear of failures 
occurring in reinforced concrete buildings after their completion, but generally during 
their erection, and although all failures cannou be attributed to defective forms, yet 
the forms are to blame in a sufficient number of cases. Although it is not the 
practice, in England at any rate, for engineers to design their forms, an engineer, 
for his own protection, should at least set out some typical portion of the forms 
for the contractor's guidance, thus doing all he can to circumvent failure in this 
direction at any rate. Of course, good forms alone will not ensure safety, and we 
have to use vigilance likewise in detecting bad work, bad design, and bad material. 

The contention that the engineer should prepare the design of formwork has 
much to recommend it. It is not merely that a design is required for a specific case 
which will safely support a certain volume of concrete, it is rather the problem of 
designing a set of forms which can be erected, taken down, and many times re-used 
during the progress of the work. 

Timber. 

The first important consideration is the timber to be used. \\'hite pine, yellow 
pine and spruce are all excellent for the purpose and should be free from knots, 
and must not be so dry that they will absorb the water from the concrete and so 
swell and bulge as to entirely distort the forms. On the other hand, if the timber 
be green it will shrink and cause the same trouble. Varieties with hard surfaces 
should be chosen in order that forms may be oftener used before dilapidation. 

The timber has to resist the weight or pressure when a considerable height of 
wet concrete is being poured, as in walls and columns. Many authorities calculate 
this pressure as a liquid of half its own weight — namely, 75 lb. per cu. ft. When the 
concrete is placed in layers no calculation is necessary, as it has been found in practice 
that for beams the bottom boards should be 2 in. to 2h in. thick, with sides 
H in. to 2 in. thick. Column sides should be i^ in. to 2 in. thick. For walls 
i^-in. boards are used. Of course the thickness of boards can be varied just as 
we place the clamps or braces, but it must not be overdone, nor the material made 



339 



THE CONCRETE INSTITUTE. [CDNQBETEI 

too thin. A more solid board will ensure greater economy, from the fact that the 
form can be used over and over again. For slab panels i-in. stuff is generally used, 
but i-in. boarding requires staying every 2 ft., li-in. boarding requires staying every 
3 ft., 2-in. boarding requires staying every 4 ft. to 5 ft. Studs should be of sufficient 
size and spaced so as to prevent the boards between them springing. 

They mav be 2 in. by 4 in. to 2 in. by 6 in. if not used beyond 2 ft. to 3 ft. 
centres; 3 in. by 8 in. may be spaced about 4 ft. 6 in. centres; 4 in. by 10 in. at from 
6 ft. to 8 ft. centres ; 6 in. by 12 in. from 8 ft. to 10 ft. centres ; but the spacing of 
the supports must be governed by the nature of the weight coming upon the boards. 

Camber. 

It is also necessary to give to beams a camber of at least ^ in. in 5 ft. — i.e.,^ljjth 
of the span. This generally comes out during the ramming and tamping of the 
concrete and in the squeezing of the wedges. After the filling, the beams should be 
examined to see if the camber has come out during the process of tamping, so that 
it mav again be secured by tightening up the wedges before the concrete has set. 

In cases where a great deflection was found in the beams, the failure of the 
supports to the studs has been the root cause, probably owing to soft ground. For 
that reason a little judgment should be used to see that the sole plates under the 
supports are sufficiently large to distribute the load safely over a sufficient area. 

Measurements, 
It should be carefully noted that the measurements are accurate and that the 
inside dimensions shown on the plan are secured, for the examination of several 
failures showed that the members were actually carried out to smaller dimensions 
than designed. 

Alignment. 

The forms should be carefully examined to see that they are truly vertical and 
horizontal and that the joints are closed so that no part of the mixture can escape. 

Cracks. 

Any cracks found in the boards can be remedied by filling with plaster of Paris 
or clay. 

Design. 

The forms should be so arranged that the slab forms and sides of beam, girder 
and cf)lumn forms can be removed first, allowing the bottom boards of the beams and 
girders to be supported for a longer time. 

Exposed Concrete. 
Extra care should be taken with the forms for all exposed concrete, which should 
be made of bevelled-edged stuff. Some use tongued and grooved, but this allows no 
opportunity to expand, and the boards cannot be used again. Undressed timber may 
be used for hacking, hut it must be watertight. 

('lamps and Nails. 
Clamps should be used to hold the forms together, as the use of nails and spikes 
so destroys the timber as to render it unfit for re-use. The pressure of concrete will 
generallv hold panel boards in place with scarcely any nailing. Where nails must be 
emjjloved thcv should not be driven home but left so that they may be withdrawn by 
means of a claw-ham nK-r. 

Rkpaik of {""OKMS. 

If forms have been left for a time exposed to the weather they should be gone 
over again and [^ropfrly aligned, and any open joints repaired. 

Economy. 

Form work should Ix- const ru(-tefl with a view to economy in taking down, rather 
than in cheapness of erection. 

Re-use. 

Before re-use the forms should be cleaned again, and the sides and ends should 
be freshlv jointed, so as to have a j)erfectly smooth finish to the concrete. 

340 



J, c^Nyrpm"riaNAi 

tVLN(iiNhKWlN<. — . 



FORMS FOR CONCRETE WORK. 



SriTI \ Ol l'\)K.MS. 

I lir luiiulx T t)| scis of Idiihn r(c|iiii cd to Ix-^iii with varies with tlx; kind (jf 
huikliiii;, tile weather eoiuHlioiis, aiul tlic sjxcd of eoiislriuiion required. 

On an aviMai^e \\ sets of forms is a "fair" allowance. With this number 
eicetit)!! on the llooi al)o\c ran hei;in while the concrete below is j^reen. Yet 
theii' are man^ iirms who use onl\ one set of forms in a building, my matter wiiether 
il he J stori<'s or lo stori<'s hij^h, with of course llu' additional timb<'r for ^irdor bottoms 
and supports left in. .\ buildinj^ of larj^e lloor area can be done in sections, setting up, 
sa\ , one-h.df of the lloor area at a time, so that the forms for only aJ)out three-fourtlis 
(^f one lloor ari' needeil with the extra beam Ixjiioms and posts. It will be self-evident 
that in a hit;h buildini.i, small in area, two sets of forms will be needed to ^et on fast 
<nou>^h. 

Cleaning of For.ms. 

.\1I forms should be cleared of all sawdust, dirt, and chips before pouring. 
Pockets or traps should be left at the bottom of the forms for this purpose. If one 
side of a pillar form is brought up board by board as the concrete is filled in, of course 
no door or traj) will be necessary. 

Wetting at.l Forms. 

All forms, if not coated with some oil, should be thoroughly wetted before the 
concrete is poured. Some persons whitewash the forms, but it is not really necessary 
if the boards are wrought and properly wetted to close the pores before the concrete 
is applied. 

Sheet Metal. 

Some authorities, in order to give a presentable surface to the concrete, line the 
inside of the forms with 20 gauge sheet metal, but however carefully this is done the 
nail-heads show. It is also liable to become indented and show an imperfect face on 
the concrete. 

Striking. 

If possible, all forms should be left one week, the beam sides being first struck, 
the bottom and strutting being left three weeks. If there is frost or continued wet 
weather, the period of duration of the frost or rain should be added to that time. 

For members of exceptional sizes, the engineer's judgment must be exercised, but 
28 days should be allowed before striking. 

Floor and Pillar For.ms. 

By far the greatest portion of the formwork encountered in building is mortgaged 
to pillars, girders, and slaibs, and it is a close and ingenious consideration of the 
application of forms to these items that seems to point the way in the direction of 
economy. 

There is a great similarity between the various types of forms for slabs and 
beams, but there are many varieties of the three types of column forms. Forms for 
square pillars as a rule are made with three sides complete and one side left open for 
tam])ing and for supervision. The fourth side is brought up as the concrete is 
deposited. Another method is to build up the whole four sides gradually with hori- 
zontal boarding, and the third method is, of course, to have the whole four sides 
entirely completed. This method demands a wet mixture, which must be poured in 
from the top. Each of these methods have their advocates. 

Steel P'orms. 

The use of corrugated steel to support floor slabs, both as temporary centering 
and to be left in place permanently, represented one of the earliest attempts to 
employ steel forms for concrete construction and has continued in use, having been 
used as lagging to support concrete floors of flat slab construction in cases where the 
corrugations on the ceiling are not considered objectionable. The ease with which 
it can be placed and moved on without apjjreciable damage and its cheapness has 
caused its adoption in a great deal of factory work, especially where the cost of 
ordinary formwork was considered prohibitive. 



THE CONCRETE INSTITUTE, \GJNCSETE1 



Tall Chimneys. 

In America Ransome's system of building chimneys largely obtains; it has made 
no progress in England. Its large square scaffold tower, with the outer and inner 
moulds suspended from it, does not appeal in this country because of its complicated 
construction. 

[Here the author threw on the screen an illustration of a chimney at Northfleet.] 
The forms or moulds for constructing the chimney consist of two rings of six sections 
held together by latches to form a mould. Two outer and two inner sets are used in 
erecting the chimnev. These forms, which are 3 ft. high, enable the chimney to be 
erected at the rate of 6 ft. per day. As soon as the forms are filled to the top the 
bottom form is released and placed on the upper form, the bottom mould being safely 
held in position by the frictional resistance of the concrete. 

The concrete is tamped round the rods, which are held to their true alignment by 
the aid of the spliced wooden guide ring of two |-in. layers placed 6 ft. above the top 
of the form, being shifted up as the chimney rises. 

Of course the working platform is carried up inside the chimney of scaffolding 
built up section by section. The framing of each section consists of four uprights 
properly braced, on top of which stout planks are nailed so as to form a square. An 
aperture is left in the platform for the hoisting of materials. 

Silos. 

In order to save timber, forms should be so arranged that they can be struck 
easih and moved up as the concrete sets. [Here illustrations were shown of some silos 
carried out by Messrs. Bradford.] The form is not only very light, but it has all the 
requirements of a good form — namely, ease of handling, economy of material and 
labour, and easv re-use. The forms are made in 12-in. heights of boards, with four 
angle posts fixed to the boarding, so that the bottom ends project i in. below the 
boards and the top ends i in. below, thus enabling one form to fit on to the other. 
Each side is obliquely cut at a greater angle than 45 degs., making the form into four 
segments, with stays at the four angles. There is a counter-sunk plate at the back of 
the form. The ^-in. hold on the concrete is sufficient to keep the forms in position, 
and they enable the forms to carry planks on top as a working platform. Three forms 
in height are always in position ; they are filled with concrete at the rate of one form 
a day, so that by striking the bottom form and placing it on the top every form remains 
in position 3 days, giving the concrete good time to set. To strike the form the thumb- 
screws should be undone and the corner pieces pulled out. The holes left by the ends 
of the thumb-screws are brushed and finished with cement mortar. 

In America the latest bin and elevator forms are on the moving principle. The 
forms consist of horizontal framing pieces to which vertical sheeting is attached. The 
form varies in height from 3 ft. to 5 ft. ; it must extend along both sides of each wa!), 
the forms on the two <<ides of the wall being connected by vertical timber or steel yokes: 
which are usually attached to the horizontal framing of the form. The boarding is 
generallv covered with sheet steel, but wooden sheeting is quite satisfactory if the 
raising of the form is carried on rapidly. In order to obtain smooth walls, then, it is 
necessary- that the forms be raised continuously, and this is generally done with screw- 
jacks, and m.'m\- of the large contracting American firms have solved the problem in 
their own way. Hridges. 

Thf [progress of concrete ajjplicd lo bridge design reads like a romance. While 
twenty years ago there was hardly a concrete arch in the United States, to-day they 
can be numbr-red by their tens of thousands. It is the same in Europe. By persistent 
efff;rl the advocates of concrete have been able to gradually convince the authorities 
that the extra cost of concret<' bridges over steel is money well expended, for the 
concrete bridge has met tlu- requirements of the ideal highway, because of its posses- 
sion of the following qualifk alions :- -. 

1. Permanence, and its increase of strength with age; 

2. Simplicity in design and erection; .and 

3. What is very important, llic r([)airs and uf)keep are reduced to a minimum. 
Therefore special att^-ntion has lM<'n paid to the forms and centering for this class 

of work, as it is the author's firm belief that concrete will come more and more into 
use for bridges in this country. 



fy^c^NMPuc-noNAi,! FORMS FOR CONCRETE WORK. 



I'Thf aiilhor ;4;i\'<' luiiucioiis illustr.itioiis of forms for v.irioiis kinds of structures 
such ;is culvtiis, concluils, silos, t.iuks, dams, etc. Ihidcr the hcadinj^ of I>omes some 
interest iiii; slides were shown of domes erect<'d in recent years in luij^land, Australia, 
ami Anu-ric^i. The MCtion " Hridi^*- " was also <'xc<'llently iliustrat^^-d, but we are 
unahK> to make reference lo the numerous examples quoted. | 

DISCUSSION. 

Mr. M. Noel Ridley, M.lnst.C.B., said lie considered the question of the many forms was 
ui all en^inwrs cngaRed in reinforced concrete construction certainly one of the most important 
tlunfTs they had to deal with. He agreed that the engineer should design the forms as far as 
poNsibhs hut »ni fortunately there were great difficulties in the way owing to the amount of 
tunher wastctl and the number of bolts lost. One of the greatest troubles they had was the 
(juestion <i f centering, and until the\- lould get a system that would obviate the amount of 
timber and strutting u]) that they had, he did not think they would overcome the difficulties. 
Timber frames were a most expensive item in the cost of reinforced comcrete and a most 
unsatisfactory item, and the sooner the.\ devised a satisfactory method of improving it the 
better. He iiersonally had, to a certain extent, gone on the lines of reducing the amount of 
centering. He had been able to dispense with all centering otherwise than two steel-wire ropes, 
and for long span bridges that type of construction, modified in certain respects, would be of 
very great use. In ordinary work he us^ed a great deal of dove-tailed, corrugated steel sheeting. 
In using that, the sheeting was left in and was not removed afterwards. It was necessary to 
id aster the under-side so as to get an architectural effect, and they were able to put in a type 
of ornamentation on their columns and beams very simply and very easily. In small domes he 
did not use any centering at all. His method of construction was light weight bars only ig in. 
by Is in., which he bent as ribs to the dome; he put sheeting in between those, then the 
concrete on the top, and rendered on the other side. 

Mr. T. A. Watson, Assoc. M.lnst.C.B., thought Mr. Graham might have devoted more time 
to the ordinary centering and a little less to the bridge work. In England they very seldom 
saw or heard of a bridge of over loo ft. span being constructed. The majority of spans in 
England did not exceed 50 ft. For that reason, and because the cost of centering for ordinary 
floor was an e.xtremelj- expensive item, he wished that the author had dealt more in detail with 
the forms of construction likely to be met with here. One difficulty they were always met 
with and always trying to find some way out of as regarded centering, was taking it down. 
It was fairly easy to construct it and put it up in place, but it was exceedingly difficult to take 
it down. He fully expected the author would have had some suggestions for the easy striking 
of centering. Referring to struts generally, poles were a great deal used amongst contractors, 
but unfortunately at present there was a dearth of scaffold poles, and tie struts were rather 
expensive, so they had to invent a new method of strutting the beam bottoms, and in order to 
make the most of the timber at their disposal they had been using recently 6 in. by 2, or 7 by 2, 
or even 5 by 2, spaced about 12 to 18 in. apart, and these things formed a sort of steel structure 
of a signal post, by which means they got for the largest diameter the excellent width of the 
centering. They got less deflection and they were able to put a greater load per square 
inch on these props than they would in the ordinary way. It seemed to him that was a fairly 
economical way oi propping centering. He did not think the author had made as much as he 
might have done of the reinforced concrete centering for bridges. 

Mr. Percival M. Fraser, A.R.I.B.A., remarked that what had been said about an engineer 
designing his own centering might apply to engineering works, but he hardly thought it applied 
to architectural works. It was a matter of contractors' plant, which an architect was well 
advised in avoiding taking any responsibility for. An architect should pay much more attentioTj 
to his specification and specify a minimum thickness for his centering. He failed to understand 
why the word " centering " should be cavilled at. Various authorities placed tne cost of form 
work at anything from 20 to 60 per cent, of the cost. That disparity showed that nobody could 
possibly lay down or estimate the cost which the centering had to the whole job ; it absolutely 
depended on the nature of the work, and it was easily much more than 60 per cent, or less 
than 20 per cent. He regretted that Mr. Graham had not given them a really good type of 
centering for a circular silo, which was much more economical in cost than the square silo. 

Mr. S. Bylaader, M.C.I., supported the use of the word '" form." and remarked that if the 
Concrete Institute adopted it, everybody would use it. 

Mr. William A. Haskins, M.C.I., as a quantity surveyor, said it was necessary for him to 
convey to many minds, by words alone, what they had to put their value upon, and, although 



E 2 



.H3 



THE CONCRETE INSTITUTE. [OGNQ2EJT3 



he welcomed the word '"form-work" as indicating the necessary preliminary structure for 
reinforced concrete work, he thought it would be altogether inadvisable to depart — in fact, 
almost impracticable for a very long period — from the customary terms. 

Mr. Cjrll W. Cocking, M.C.I., asked Mr. Graham what his factor of safety was for the 
stresses he gave for timber pillars. 

The President said he found the relation the cost of centering bore to the cost of the work 
varied between lo per cent, and loo per cent. It could, therefore, be easily understood that 
where contractors were, as a rule, given the cube of the concrete and had put on the cost of 
centering, how lamentably they must be at sea. 

Mr. ALLAN GRAHAM'S REPLY. 

In replying, the author stated Mr. Watson had adversely criticised the American form of 
centering, but that form had been criticised for ten or twelve years, and it was the result of ten 
or twelve years' criticism — the accumulation of facts and the accumulation of practice. He 
was afraid it was a misnomer to call it the English practice, because there was no practice ; 
every job they went on they found a different style adopted. It was that very different style 
that enabled joiners to uie their material up for all they were worth. Replying to Mr. Fraser, 
though an engineer had no blame whatever for the centering, if an accident happened in a 
building for which he was the engineer, the odium would attach to him just the same. That 
was the reason he protected himself by saying if they did ^jot do the centering themselves they 
should make the contractor submit his idea for approval. With regard to the cost of centering 
he had known a difference of as much as 30 per cent, between two different contractors tendering 
for the same job, so there must be some standardisation or else they would never get any 
further. Circular silos were more generally erected in America, but nearly all the silos in 
England, with few exceptions, were square. That was the reason why he gave the two types 
of ordinary centering. Referring to Mr. Haskins' observations, he explained that he was not 
concerned with the finishing of the building at all, but only with concrete structures as concrete 
structures from the surface. In answer to Mr. Cocking, the greater portion of the formula he 
used was based on the Rankine formula, but when they got to a certain height he shifted over 
to the Euler formula, as being square. 



3+4 



'a, CONMPl IC-riON A \] 



THE METROPOLITAN RAILWAY. 



NEW WORKS IN CONCRETE 

AT HOME AND ABROAD. 

Under this heading reliable information tvill be presented of neiv ivorks in course of 
construction or completed, and the examples selected ivill be from all parts of the "world. 
It is not the intention to describe these ivorks in detail, but rather to indicate their existence 
and illustrate their primary features, at the most explaining the idea "which served as a basts 
for the design.— ED. 



REINFORCED CONCRETE IN THE NEW OFFICES OF THE 
METROPOLITAN RAILWAY. 

A iiANDSOMK buildini^ h.is qiiit<' na-ntly lx'<'n i-xecutod, almost ontirely in rcinforcod 
concii'to, for th<' acconiniodation of tlu' staff of the .M<'troj)(>litan Railway, so that the 
j)r<'vious ortiros which w<M-e scatti'red in various parts of the company's system are now 
canc<Mitrat<'d under one roof. 




1 iuiii i:,ic\ diii^ili. 

Reinforced Concrete in the New Offices of the Metropolitan Railway. 



345 



NEW WORKS IN CONCRETE. 



ICDNCRETD 



For reasons of better economy and efficiency, the new offices have been constructed 
partly over the various lines of railway. This, however, has necessitated a considerable 
amount of forethought in the planning of the structure, in order not to interfere 
with either the existing or future traffic. 

Various firms of specialist reinforced concrete engineers were invited to compete 
for the general scheme in this material, and, after very careful consideration of the 
merits of each particular system, the Coignet system was selected for the preparation 
of all the plans and technical information required for placing the work in competition 
amongst contractors accustomed to reinforced concrete construction, and also for the 
preparation of all the working drawings. 




Ground I'lan of First Floor. 
Keiniokced Concrete in the New Offices of the Metkopolitan Railway. 



A certain numbf^r of contractors comjx^ted upon the s<'k'cted scheme, and ullimat<'ly 
the ■execution of lh<* work was giv^-n to M<'ssrs. Ik-nry I.ovatt, Ltd. 

'J'he reason for adopting this UK-thod of j)r()cedure was in order to obtain the 
best j>ossible results, both in cU-sign and in the actual execution of the work. The 
plans and the sufK'rvision of tlK' r<'inf()rc<'(l concrcl<' work were entrusted to M<'ssrs. 
Rdmond Coignet, Ltd., of 20, Victoria Str<'<'t, \V<'slminst<T. 

The photograph which w<' r<'pro(kice shows th<' front ^'Icvation, which was carri<'d 
out in brickwork and special fai<n(.c forming a facing to th<' r<Miiforcc(i (■oncr<'l<' work. 

The architectural front on this building was d<'sign<'d by th<' ICngini'crs' Archi- 
tectural Assistant. It will be notic<'d that some of the dccorativr features — 

346 



E 



y, CONM yUCTIONAl 



THE METROPOLITAN RAILWAY. 



n.-muly, th<- hioii/r l»uH<is .iiid coiipliiii^^, \\1m<1s .iikI sij^n.'ils — cl<».arl\' (l<-ii()t<- tlir 
associ.ition of ihis huildiiiL!; with tli<' railway. 

riu- harU <'l-('\ati()ii, lu)\v<'V<'r, coiistrurt^d ()\<r iail\\a\ liii<-s, lias l><<n (Icsij^iKii 
w itli -4i-<at simplii'ily, paitly for tli<' sak<' of <(()iioin\ and parlU' owin^ to IIk- fact that 
ihis |)ortioii of llir hiiijdiiii^ is |)ra(ii(all\ liidKUii from \i<-\v 1)\' the roofs ovrr lli<' 
j^lat forms. 

'I'Ik' total Kni^tli of th<' front <'l<'vation is aboiil 140 ft., and th<- total iKJLilii 
(m<'asui'<(l from llu- foundations to the loof) is aj)])ro.\imat<'l\ 90 ft. 

Thr hack portion of tlu' huiklinj^ is C()mj)os<'d of two winj^s, nu'asiirin<4 r<'S|X'Ctiv<'l\ 
111 ft. in U'lij^th by 3S ft. in width, and 100 ft. by 43 ft. for th<' smalk-r winj^. The 
latt<r is ronn<'Ct<'d ti> the bookinj^-hall of th<- ik-w station, facinj^ Marvk-bone Road, 
bv a st<x'l footbridife. A retainini>' wall in ri-infora'd concrete has been constructed 










Section of Board Room Roof. 





f' 








n 




















fy 


? 


. <&«' ■Kf J 




\ 
















3^ /.3a.is 




I 


1 t ■ fi 


1 


i 


i 

J 












i 


tt^^t/aa 




I 














— 






/^M>»jia 


-r 








— 1 
















, . , fl»' Sffe 


\ ' 










— 


R 


: 


R 
















X 






anmrao 














n ^ 


M 


-t 


qoca 


Lj 




i 3 ' 
i ^''j ,„ 


^ 
^ 


^ 


1 ^ 




Sbr^rsoe 



t^ tr* f.x* .>t^5=-=---^=^J'"^«a>«=f«ta^--jnij£:=:jJa3.^_^z^^' 



Section. 
Reinforced Concrete in the New Offices of the Metropolitan Railway. 

along the front on a length of 152 ft. and with a height of 24 ft. This retaining wall 
has been provided to form the basement of the structure, and it is arranged so as to 
allow the proper lighting and ventilation of the lower portion of the building, below 
the upper ground level. 

The building comprises a lower basement, basement, booking-hall floor, ground 
floor, first, second, .and third floors, and a flat roof. A superload of 150 lb. per sq. ft. 
has been allowed up to the first floor level, inclusive. 

The upper floors are calculated for a superload of 90 lb. per sq. ft., and the flat 
roof for a .superload of 40 lb. per sq. ft. 

The total suj^erficial area of the various floors and roofs in reinforced concrete 
amounts to approximately 65,000 sq. ft. 

3 + 7 



NEW WORKS IN CONCRETE. 



[CQNOaTEl 



The fjround floor at street level is for the accommodation of the principal suites of 
offices and the board room, of which a j)hotoora])h is herewith reproduced. This board 
room is provided with a dome in reinforced concrete. 

It is situated between two committee-rooms, and, by a special arrangement of 
disappearing partitions, it can be enlarged to hold the meetings of the company. 

These rooms are panelled in hardwood, with double partitions and windows to 
s-hut out any noise from the railway below. 

The engineer's office is placed in the north wing, so as to get the maximum 
amount of light for the drawing-offices. 

The two back wings of the building are supported by massive reinforced concrete 
pillars and beams over the new platforms. 




\'icvv of Board Room. 

Kl.INI OKCKD CoN'Cr<ETE IN THE New OmICES OK THE METROPOLITAN RAILWAY. 



Th<- low<-st floor of th<' building is on a 1<'V<'1 witli th<> booking-hall of th<' new 
station. 

']"he h<'ating ch«amber, stor<', and strong-rooms are situalcd al a lower 1<'V<'1 and 
alongsid<' a s<'t of rails, to facilitaW- {]]<■ handling of the coal for h<'ating purposes, also 
for th<' handling of store's. 

'J'h<' staircase's hav<' automatic lifts. The lift on IIh' south sicic is arrangexl to 
descend to platform U'V<1 for tin- j)iirj)Os<' of collecting and (l('sj)atching cash, tick<'ts, 
and documents. 

Th<' north staircase- lift is connected willi lln' accountant's and other <l<'partm<'nts. 
Th<- lift (U'sce-nds to th<' strong-rooms in ilic base-UK'nl. 

'I"h<- l<it(li<'ns, (lining-r(jonis, and (arctakcr's quarters are all situal<'<l on the toj) 
floor. 

348 



/.' 



CONMPlK'nONAl 
fcJM(aNhFJJlN(. — . 



TIJH MhrPROPOLirAN RAILWAY. 



Vhv <'iitir<' huildinj^ is h<;il<(l l)y iiK'.'ins of r.'idiatois with low-pivssinv liol \\;i(<'r. 
'\'hv doors .iir (■o\'(r<(l by ni<;ins of woocUn blocks. 
'rb<' coinp.tiu \ < iiLjin^H r for llir work was Mr. W. W'illox, M . Insi. ('.!<'., his 




assistant, Mr. C. \V. Clark, havino carried out the architectural work, and his resident 
engineer being Mr. O. G. C. Drury, A.M.I.C.E. 

The lifts installed are those of" Messrs. Wavgoods, Ltd., and Messrs. Beavan and 
Sons, Ltd., supplied the radiators. 

3+9 



NEW WORKS IN CONCRETE. 



ICDNCRKIliJ 



REINFORCED CONCRETE BRIDGE IN CALIFORNIA. 

The bridge here illustrated was built jointly by the City of Pasadena and County of 
Los Angeles across the Arroyo Seco. The work of construction was started in June, 




View showinf^ Main Span. 




View taken lioi.i VVest-cM.i.ot lirid^e lookin>i towards I'asadena. 
Rkini'orcki) Conc.kkik Hkidgi-. in Cai.iiornia. 

rs! :;:: ^iprV/xi,;;.;:"; $:,.,,„.„. l... ....„ ..,, ,n,lu.,in, n,h,. of way, lK.av, 



35° 



r J, CTONM PUtTlONAi; 
[t\ ENdlNLlrJJlNd — -. 



REINFORCHD CONCRETE BRIDGE. 



cuts, ami const ructini^ houUv aid 1)\ lh<' County to conm-ct with the west <'n<J of hridj^e, 
was $240,000. 'lluK- ar<' 4'l<v<-ii main sj)ans, witli a total k-nj^th of i,467"5 ft., 
IncUuliiiif appiHJai Ihs. IIk'H' is a 3<S-ft. roadway with 5-ft. si(i<-walUs on <<;s'ich .side. 
Th<' loni^est span, whicii is din-ctly over th<' h<d of th<' Arroyo, is 223 ft. from c<'ntre 
to crnir<' of |)iers, with a h<'i^ht of 150 ft. above the Ix-d of th<* Arroyo. As will be 
ni)t< (1 in tJK' acconi|)anyini4 illustrations, the bridge was huill ])arlly on a curv<'. This 




View of Bridge looking North, 
Reinforced Concrete Bridge in California, 

was done in order to obtain the most economical point for crossing the main part of 
the Arro}o and avoiding a large expense for ])iers. The bridge was designed by 
Messrs. Waddell and Harrington, of Kansas City, Missouri, w^ho also had entire 
charge and supervision of the construction. The Mercereau Bridge and Construction 
Company of Los Angeles, California, were the contractors for this work. We are 
indebted to Mr. Lewis E. Smith, the City Engineer of Pasadena, California, for our 
particulars and photographs. 



351 



NEW BOOKS. 



[CDNCBETEJ 



NEW BOOKS 

AT HOME AND ABROAD. 

A short summary of some of the leading books 'which ha-ve appeared during the last feiv months^ 



"A Text-BooK of Elementary Building Con- 
struction." By Arthur K. Sage and 
Wm. E. Fretwell. 

London. Methuen & Co., Ltd., 36 Essex Strte', W.C 
29j pp. + viii. Price, 3/6 net. 

Contewts. — Introduction — Brickwork — 
Masonry — Iron and Steel — Carpentry 
— Slating — Plumber's Work — Joinery 
— Joints, etc., in Pipes — Sanitary 
Appliances and their Connections — 
Board of Education Examinations. 

There is a great need for a really good 
text-book on Building Construction which 
could be given into the hands of a student 
with the confidence that he would be able 
to do really useful study and acquire 
sufficient knowledge to form a ground- 
work of sound construction and enable 
him to proceed to the more advanced work 
almost unaided by personal tuition. Such 
a text-book could only be prepared by 
someone who had been in actual contact 
with students of all kinds, and we are 
pleased to note that the authors of this 
\T)lume are both lecturers at the Brixton 
School of Building, and as such they must 
be well acqiiainted with the class of reader 
to which their bo<^)k is presented. We are 
glad to see that notes on materi.-ils have 
been introduced, as these are absolutely 
essential, and there is no justification for 
leaving this part of the subject out of an 
elementary work, as the student must 
understand the nature and limitations of 
the various materials before he can fullv 
appreciate their application to building 
problems. 'I'here are various criticisms we 
should like lo make, particularly with 
regard lo some of the diagrams, hut spnce 
will not permit this, and after .ill, it niusl 
be admitted that it is easir r to (riticise 
than produce a perf-ct work'. 



There do not appear to be any notes on 
plastering or painting, and this is to be 
regretted, as it would have made the 
volume more complete. Generally speak- 
ing the book is well written and should 
appeal to elementary students, while the 
price is so small that it should be within 
the reach of all readers and thus become 
popular as a text-book for class purposes. 

"Portland Cement Manufacture" (Die Port- 
land - Zement - FabriKation). By Carl 
Naske. 

3rd Edition. 496 pp. and 408 illustrations. 1914. Leipzig' 
Theo-d. Thomas. Price M. 22. 

This excellent handbook has now reached 
a third edition. Its general features are 
well known, and have been retained, the 
only entirely new^ section being a short one 
on the quarrying of the raw materials! 
The principal methods of manufacture, 
and the machinery and plant employed in 
the process, are very clearly described, and 
illustrated by means of clear sectional 
drawings, the latter being a welcome relief 
from the reproductions of photographs 
from makers' catalogues which commonly 
do duty in works of this kind. The 
progress of the industry since iqoSj the 
date of the last edition, h.'is been so rapid 
as to necessitate the re-casting of several 
sections dealing with crushing and grind- 
ing, transport and storage, and the 
removal of dust. On such subjects as 
these the book is a mine of information. 

The brief section on testing has received 
less attention than the remainder of the 
book, and would not be found adequate by 
workers in this country. On the other 
hand, the official specifications now oecupy 
loo pages, and include all those which are 
now accessible from Japan to Chili. This 
section will be foimd useful bv many. 



352 



A ENCilNl-l-klNCi — . 



CONCRETE PILES 



INDUSTRIAL NOTES. 

These pages hji>e been rvscn>eJ for the pre sentaiion of articles and notes on proprictjrj 
materials or systems of construction put forv.>arJ by firms interested in their application. With 
the adi'ent of methods of construction requiring considerable skill in design and supervision, 
many firms noivadays command the sen>ices of specialists ivhose iJiexus merit most careful 
attention. In these columns such 'viexos ivill often be presented in fa'vcur of different 
specialities. They must be read as ex parte statements— ivilh ivhich this journal is in no way 
associated, either for or against— but ive ivou Id commend them to our readers as arguments by 
parties toho are as a rule thoroughly conversant tuith the particular industry ■with -which thev 
are associated. —ED. 



CONCRETE PILES. 

TiiK sysli'm of makinj4 concix'to j)ik's by cirivin^:^ a lube with a shoe into the jfround, 
leavinj^ the shoe behind, fiUinj^ the tube with concrete, and then withdrawing it, as 
protected by John Potter in 1864, is well known, and the system her<'in describ<'d has 
been devised with the object of obtaining nior<' satisfactory piles by compelling the 
concrete to effectually fill the void created by the w^ithdrawal of the tube, and it is 
the invention of Mr. T. W. Ridley, of Messrs. Thos. D. Ridley and Sons, Middlesbrough. 
The first part of the patent refers to the joint between the preparatory tube and 
the shoe, which is a double or trii)licate one made by a quantity of Tuck's or other 
like packing and clay on each side of it. This packing is jjut underneath the bottom 




Pull Luici indicate 
AFparstu^ before 
t'ftinf ind 
Dotted Lir 
position af 
opor*»iani 




Fig. 1. 

of the preparatory tube and in the recess in the shoe, with the clay on each side, as 
shown in Fig. i. By very simple arrangements the tube and the shoe can be tempo- 
rarily connected together, so that, like an ordinary timber or concrete pile, they form 
one piece. 

The second part relates to the withdrawal of the tube and the compression of 
the concrete at the same time. This is done by a series of links fixed to the top of 
the preparatory pile, shown on the drawing in Fig. 2. The apparatus is first lifted 
or raised above the driving head of the tube by two links (.4), which are fastened to 
the tube by lugs cast on each side. To A are pinned two links (B), and these again 
are pinned to each of the two pairs of links (C and D). Between the links D is fixed 

353 



INDUSTRIAL NOTES. 1 CQNCBETE3 

a ramrod, which is in the form of a tubo with a piston on the end. When the lifting 
power is applied at the top, where the links C meet, B and C tend to come in a straight 
line, and the links D are depressed and so force down the ramrod, which then causes 
the concrete to be forced downwards as the tube is lifted. The compressing force 
practically equals the resisting power or the suction of the ground or friction on the 
tube in withdrawing it ; and as the tube approaches the top it may be necessary to 
increase the compressing power by clamping the tube to the piling frame, making the 
tube more difficult to draw, but giving the necessary compressing force on the concrete. 

For the foundation of a bridge at Seaton Carew, Messrs. Ridley were allowed to 
use this pile, on the condition that they satisfied the designers that the concrete 
adequately filled the hole made by the withdrawal of the tube. Two piles were driven 
and afterwards dug out. The tube used was 13^ in. internal diameter, and in no 
case was the column left in the ground less than 15-5 in., while where the foundation 
was peatv the column was nearly 20 in. With this system it is claimed that it is also 
possible to form a foundation having a reinforced cast concrete column inserted in the 
preparatory tube, in which also is placed a quantity of fine liquid concrete ; then by 
means of the compressing arrangement this column is forced down into the shoe, and 
the liquid concrete will, as the tube is withdrawn, take the place of the metal of the 
tube and thoroughly surround the cast concrete column. 

The latter method is used in connection with works in water, and in such cases 
the shoe and tube are temporarily connected, as previously described, making the 
watertight joint, and this shod tube is then driven down to the necessary depth and 
the two are disconnected. When this is done, liquid concrete of very fine material is 
placed in the tube, and the previously moulded cast concrete column inserted, the 
latter having upon it a flange which is an easy fit inside the tube. This column is 
forced down by its own weight or other easy means until the liquid concrete has risen 
to the underside of the flange. The withdrawal of the tube and compressing will 
then be worked in the usual way. The cast concrete column will thus be forced down 
into the shoe, and the liquid concrete will follow the tube up to the ground line, and 
form a ring or collar of concrete around the cast concrete column, and fill up the hole 
in the ground. When the tube has left the ground, the surplus concrete, if any (and 
there should be sufficient to form a surplus), will be left close to where the flange is. 
In this manner a reinforced concrete pile — reinforced and designed purely and simply 
for the load it has to carry- — can be inserted in the ground and made secure without 
being damaged in any way by driving, the only difference being that there is a flange 
at or about the ground line. The function of this flange is to act as thei ramrod or 
the compressing force, causing the liquid concrete to rise out at the bottom of the tube 
and up around the column itself as the tube is lifted. 

As an example, the following particulars are given for a foundation pile about 
30 ft, long, using a 14-in, internal diameter tube, which would eventually leave a 
column about 16^ in, diameter, in the centre of which would be a cast concrete 
reinforced column 11^ in. diameter. The units are the superficial inches multiplied 
by the length in fe<'t. This may be jwrhaps more readily understood than bringing 
the figures down lo cubic feet. 

Ft. Sq. in. Units. 

Finished pile ... ... ... 30 ft. long x 16^ in. diameter =30x213 =6,390 

Finished cast concrete rohimn ... 30 ft. long x iii in. diameter =30x104 =3,120 

Finished concrete case ... ... 30 ft- long x 16^ in. - 11^ in. diameter = 30 x 213 — 104 = 3,270 

Contents of prei)aratory tube ,,, 30 ft. long x 14 in. diameter =30x154 =4,620 

Difference between cast fonf:refe 

column and f:ontc'nts of tubc 

30 ft. each ... ... ... 30 ft. longxi4 in. — ii^ in. diameter = 30 x 154 — 104=1,500 

'J'h<'r<'fore 3,270—1,500 will he n<<-d<d to ins<'rt in th<' tulx' before the cast concr<'t<' 
column is placed in [Kjsilion; 1,770-^154 gives nearly 12 ft. in length of tube. This 
gives practically two-fifths of th<' 1^'ngth of the pik'. Th<' foremrm driving a pile, which 
in this case is 3f) ft. long, wcaild know that Ik- has to j)ut into the tube 12 ft, of its 
k'ngth of i]u<- liquid concrete. 

Th<n \hv cast concrete column would Ix- allowed to s<'ttle by its own weight or 
that of the tackle to ^-nsur^- th<! concrete rising up to tli<' piston, which piston can be 

.354 



^ 






CONCRETE PILES. 



i'itlur llu' ()r<lin.ir\ |)ivton oi oiK' s|)<ci;illy cast on lli<' column, as in riv<T or \\al<'r 
work. If tlur<' \v;is not a >-nirici< ni c|nanlily of liquid concr<t<' to do this, nion- would 
ha\c to he inserted until the iLinj^e was reached. Then the ordinary pressing' arran^e- 
nu'iit and withdrawal would Ix' s<'t to work, and the conii)r<ssion woidd tak<' |)!ac<'. 
A |)ik' ^o ft. liHii^ shoidd onh' ha\<' to Iw forcid 1)\ ih<' conij)r<'ssion ahout u ft. One 
of 40 ft. would ha\'<' to Ix' forc<(l ahoul i() fl., whilv ()n<' of 20 ft. would (jid\ n<ed 
about S ft. of forcing;. '\']u- oilier |)oilion should sink hy its own wx'ij^ht. 

In th<' cas<' of a i-olunm in ii\< r work, wh<'r<' llu' \nU' its<'lf is not to Ix- forc<-d down 




Fig. 3. 

below the ground, the flancje would have to be made at or about the ground line, and 
the liquid concrete all put in, as it could not be passed below the flange after the 
column was inserted. 

The photograph illustrated in Fig. 3 shows two piles that have been formtd 
according to this system, and afterwards excavated; and it will be noticed that the 
fine liquid concrete has spread out in the soft strata and increased the diameter of the 
pile, thus achieving the inventor's object in compressing the concrete during the 
withdrawal of the tube. 



355- 



MEMORANDA. 



[CDNCBETEJ 




Memoranda and Neivs Items are presented under this heading, with occasional editorial 
comment. Authentic neivs ivill be ivelcome. — ED. 



The Iron and Steel Institute, — We are asked to state that the annual meeting 
of the Institute will be held, by kind permission, in the new house of the Institution 
of Civil Engineers, Great George Street, Westminster, on Thursday and Friday, May 
yth and 8th, commencing at 10.30 a.m. each day. Full particulars can be procured 
from the Secretary, Mr G. C. Lloyd, 28, Victoria Street, S.W. 

Liverpool Architectural Association, — A paper was recently read before the 
above Association by Mr. John A. Davenport, M.Sc, on " Concrete and Reinforced 
Concrete Don'ts for Architects." After some preliminary remarks dealing with 
concrete, centering, and steel, the author went on to deal with the subject of fire 
resistance and economical design. In connection with the subject of fire resistance 
the author stated that the fighting of fires was the work of municipal authorities, but 
appliances should alwavs be available to deal with an outbreak on the spot. 

Fireproof walls, roofs, and partitions should be used to prevent spreading, but 
these would be of little use if the coverings to window, door, and other openings were 
not as strongly resisting as the rest. After localising the fire, attention must be paid 
to the protection of all structural members, whether built of steel, wood, or stone, 
and the best material to use is concrete. But the protective coat must be of uniform 
thickness for best results, and this prohibits the bedding of pipes, ducts, etc., therein. 
The object of the coat is the protection of the steel, and therefore there must be no 
passage for the heat to flow from the outside to the inside by way of wood plugs, 
metal projections, and so on. 

Turning to the subject of economy in design, the lecturer said that economy 
depends upon cost of materials and cost of labour, which will vary from time to time; 
but these mav be taken at present-day values for comparisons. Neglecting all question 
of architectural economy, the cost of the engineering structure is affected chiefly by 
the lay-out or arrangement, next by the relative amounts of concrete, steel, and timber, 
and also bv the shapes of the sections used. The most economical job is given by the 
us^^ of thin slabs support^-d by beams of shod span, the whole being reinforced with 
steel of perc^entage slightly higher than the theoretically economical percentage. 
Uniformitv of sizes makes for economy, as with dissimilar sizes much time is taken 
in k-arning to f;ut in the st<-(l .ind concrete expeditiously. OiIkt things of importance 
to <x:onomical d<'sign are th<' choici' of suitabk' and ch<'ap aggregat<'s, and the adoption 
of ste<l size's which can be purch.'ised ch<'aj)ly and b<' worked and hrmdled easily. 

A list of concr<'t<' and r<inf()rc<(i concrete don'ts Ix-ariiig on the points raised in 
th<' j)aper was giv^en, and vi<-ws of r<'inforced concr<'t<' failur<'s, lh<' j)ulling-d(>wn of a 
reinforced con(T<-te buikling, and th^e < r<'Ction of reinforced concrete buildings were 
shown and described. We give below a few of the " Dont's " nuntioned : — 
Don't use any cement that does not satisfy lUitish standard si)e(ifirat ion. 
Don't use a sand which is coated with clay or contains any nvitcrial which will alTcct the 

settinj^ or stren/itli of the f:einent. 
Don't use coke breeze, brick, or any olhcr l>()ro^^ auk'rc/^'alc when a waterproof concrete is 

wanted. 
Don't mix the concrete too dr\- ; a wet mixture is niiK h easier to work. 
Don't let any time elajjse Ix-tween the mixing and laying,' of the concrete. 
Don't use any batch after it has (ommencefl to ijel. 
Don't lay concrete in frosty weather. 
D<m't leave bags of unused cement on the /.(round and exposed to llio weather. 

3S6 . 



(g^^^^ MEMORANDA. 

l)<)n'l liavc wimU ri-iitcrin/^. 

l)c)n'( lorf^t'l that tlir inoiiMs sliimld Ix- (If.iiud out lu-lort' llii' con ( ret f is laid. 

l)<)irt have (tnlcriii^; up x) U>nK that it (ifhi.\s liardi-niiiK- 

Don't loif;et to }.;i\r a little cainhcr to hcanis of lon^; span to compensate for deadweij^ht 

dellect ion. 
Don't construtl fc.rni> for deep work in sin li a w.ix thai the eonerete nnist he jjonred in from 

f,'reat heij^ht. 

Steel Po>r/s. 

Don't use a steel that tloes not comijlv with tlu^ Hritish standard or the jn<l R.l.H.A. Rei)ort 

Speeificat ions. 

Don't allow steel to be welded. 

Don't allow eonerete to be laid before steel has been seen in the moulds and approved. 

Don't let steel be displaced when the concrete is rammed. 

Don't let steel be exposed to atmospheric or an\ other rusting influences. 

Don't allow the steel to be bent or worked hot if it can be avoided. 

Fire-resisting Doi'ts. 

Don't omit fire-resisting partitions in any building. 

Don't leave unprotected openings in walls, windows and roofs. 

Don't leave any structural members unprotected. 

Don't leave wood plugs in the protective coatings, as these are easily burnt out and expost 

the interior. 
Don't embed pipes, mains or ducts in the coating. 
Don'i allow a thickness of coating of less than i in.* 
Don't use a porous concrete without covering the steel with a rust preventive. 

Some Tests on Strength of Overwet Concrete. — .Some data have been compiled 
by the Committee on .Specifications and Methods of Tests for Concrete Materials, of 
the American Concrete Institute, in connection with an extended investigation into 
a standardisation of concrete test pieces, ix'oardino the deleterious effect of too much 
water in concrete. While the tests were made in an effort to arrive at a proper 
proportion of water to use in mixing test pieces, they at the same time went to show 
definitely the effect of a variation in water content which must be of similar, although 
not necessarily proportionate, importance in field work. 

The tests reported were made under the same prescribed conditions of standardisa- 
tion and manipulation, but with necessary local variations in material, by three college 
laboratories. The concrete was ajjproximately a i : 2 : 4 mix, with coar.se aggregate 
of from h in. to f in. in diameter. Each value given is an average of four 6-in. 
diam. b\ h-in. cylinders. The amount of water used varied with conditions of sand 
and gravel, but the consistency is described as follows in the Committe<''s report : — 

Because of the difference in the effect of different sands upon the consistency, it was 
impossible to specify a definite percentage of water. Tests made by members of the Committee 
indicate that the most uniform degree of consistency can be obtained by adopting the Chapman 
consistency test, wdiich consists in filling a slightly tapering cylindrical form with concrete, 
immediately inverting this, and by repeated trials finding the amount of water which will 
cause the concrete to just begin tO' slump when the form is removed. A dry mix is, of course, 
unsatisfactory, while it is almost impossible to describe a very wet mix which will insure 
uniformity. 

Speaking generally, however, the dry mix is about 8 per cent, water, the normal 
about 9 per cent., and the wet 10 per cent. These perc<'ntages, it will be appreciated, 
are much lower than those required to give similar consist<'ncies in actual concrete 
work, but the comparison is the same. 

The accompanying table gives the actual compressive values up to sixty davs and 
the curve the average of the three laboratories for the three degrees of consistencv. 

* Tn ou/ opinion this minimum is too low. 

^ 357 



CQNCDE:rE« 



«>gri=-d k-=ii=~< N>=^i=c^ W-^i=^ \x..^i;=..i ..=^i=^ l^.=i!=«< ^o=;>o^ ^~=s^ i».=ii==:g 



I 
1 






SIMPLEX 

STEEL SHEET PILING 



Illustration 

shows 

Simplex Piling 

being driven 

under 

difficulties 

in India. 

The only plant 

available was a 

small drop 

hammer. 




This is 

only one 

of the very 

many instances 

where 

Simplex Piling 

has been 

used to 

advantage 

in difficult 

positions. 



OWING TO ri'S LIGHTNESS IT CAN BE 
EASILY HANDLED, & IN SHORT LENGTHS 
CAN BE DRIVEN WITH A HAND MAUL. 

SIMPLEX PILING IS SUPPLIED IN TWO 
WEIGHTS, i.e., 22 & 27 LB. PER SUPER FOOT. 



Our Piling may be had on hire at the following approximate prices : — 



Simplex Piling, 22 lb. ... 
Simplex Piling, 27 lb. ... 
Universal Joist Piling, 43 lb. 



lid. per super foot for the job 

1/3 

1/10 



»> 



THE BRITISH STEEL PILING CO., 

4 DOCK HOUSE, BILLITER STREET, LONDON, EX. 



Telc()honc AVKNIJI': Slf.l. 



:l(t;r;iiiis— " I'lI.INflDOM, LONDON." 



^ y>.=^^,=^ ho-=::it:^ k-=4i^=^ h ^^^^^,^^ k>^^^^ cx>^:4^:^ k<^t^ l«>-=^^^^ ^po-^^HP ^ jcxx^^^ 



358 



Please mention this Journal ivhen ivriting. 



.CDN.srPUCJIONAl. 
KNdlNl 1 RlNti --. 



MEMORANDA 



I Alii. I. SIK )\\ I \( 



I I I ICT ()!■■ WA'I'I.R PKKCl-.NTAC.l'. C)\ ( OMl'KI^SSIVK 

xc.rij ()!• (■()\( ui/ii', ()x6-ix. CN Li\i)i-:ks. 

Avtr.ifj;c (oinpiH-ssive stn-nj^lh, lb. piT s(i. in. 

Mass. Institute 



Ihiive 
A«r. Dry 

- <l;i>s 1751 

14 (la\s 2140 

.21 (lays -^(isS 

28 <lays -2615 

2 months 3056 

* io'2 ])er cenl. 



rsily of 


1 llinois. 


I'niversitx of \V 


isronsin. 


<.f 


're( hno 


ogy- 


Norma 


. Wet.* 


Dry 


Normal 


. Wet.t 


Dry. 


.Norma 


l.Wet.: 


i.?<)o 


1 103 


1 (k^o 


15,80 


9>?,i 


2047 


1740 


065 


1775 


I3.S4 


■2 7<).S 


I <J05 


600 


274-2 


2320 


1372 


i8i() 


1623 


-2450 


20(i5 


722 


2S'J4 


23g6 


1464 


1820 


1657 


2380 


-2430 


860 


2670 


2882 


i8y5 


.30(13 


2410 


2485 


2340 


787 


2;6i 


30(J2 


1830 


water. 


t I2"0 


|)er cent. 


water. 


+ lo'o per 


( ent. 


water. 





Reinforced Concrete Telegraph Poles versus Wooden Po/es.— The .suixriority 
of rt'inforcxxi conci'tU' for ivU'j^raj))! poh's ()\<t th<' ordinary w ooclcn j)()k'.s has eslablish<''d 
its^elf in the recent blizzard in N<'\v York. The Engineering Record reports as follows : 
" The storm centre was in and about New York City. The wind blew at a velocity 
of eii^hty miles per hour, and there was a heavy fall of snow and sleet. As far as 
telei^raphic communication was concerned, New York was isolated for several days. 
So severe a load did the ice-coated wires impose upon the concrete poles that the 
wooden cross-arms on some of them were broken. The poles themselves, however, 
remained intact." Photoi^raphs which accompanied the above report show some 
wooden poles, after the blizzard, broken ri<4ht throu<^h, whereas an illustration of some 
concrete poles shows these quite intact, excepting for the damage above m<'ntioned. 

Removal of Concrete Forms. — The committee on reinforced concrete of the 
Canadian Society of Civil Engineers has submitted to the society a draft of proposed 
standard specifications for plain and reinforced concrete. These specifications contain 
a clause entitled " Form Removal," which reads as follows : 

"The forms shall not be removed until the times named in the following table 
have elapsed after depositing concrete, not counting periods in which the temperature 
has been below 35 deg. Fahr." 



Port. 

Posts under beams and girders 

Floor-slab panels ... 

Wall forms ... 

Column fojms 

Sides of beams and girders 

All other parts 



Minimum 24-hour day. 



20 
10 

2 

4 

4 

10 



-Enc^inecrin^ Record. 



Concrete Dwellings House at Norwich. — We are asked to state that the concrete 
block dwelling-house at Norwich for the foreman engineer at the Norwich Main 
Sewage Pumping Station, and illustrated in our April number (page 285), was built 
of " Winget " blocks made on " Winget " machines, installed by the Norwich Corpora- 
tion some time ago. 

TRADE NOTICES. 

Martin's Adjustable Scaffold Brackets. — Our attention has been drawn to some 
patent scaffold brackets, of which we give an illustration herewith. 

'Jliese brackets, which are made of steel throughout, are largely used in place of 
the ordinary scaffolding, built up from the pavement and swing cradles hung from the 
roof. 

It is claimed that they are extremely light, yet very strong, and can be fitted by 
unskilled labour in two or three minutes ; they can be used for any number of jobs, and 
when not in use can be stored easily, as each single bracket is only 4 ins. wide. 



F 2 



359 



MEMORANDA. 



ICONCBETEJ 



Thev are fixed, at any window openinf^, from the inside of the 
building^ bv m<'ans of square threaded steel screw and handle, the 
wood blocks which clamp ag<ainst the wall bein<4 i)added with thick 
felt. 

Double brackets, about 2 ft. 6 ins. wide, are made with fixed 
wood platform and handrail comjjlete, and are suitable for working 
at a fixed position. 

Single brackets may be fixed at each window of a building, 
and scaffold boards laid from one to the other, thus providing a 
continuous platform along the front of same. 

It is claimed that these brackets entirely save the cost of expen- 
sive scaffolding, cradles, etc., and so easily pay for themselves on the 
first work for which they are used. 

The sole manufacturers are Messrs. E. A. Reed and Co., Ltd., 
of 14, \'ictoria Street, Westminster, S.W., who will be pleased to 
send full particulars and prices upon application. 

Asbestos Cement Tiles and Boards. — It is claimed for these 
boards that they are extremely useful as permanent centerings in 
certain concrete constructions. Once the old-fashioned wood centres 
are removed, the work has generally to be faced up with cement and 
sand. Where asbestos cement sheets are used the wood centres may be 
spaced wide apart, and the asbestos cement sheets put in situ with joints inside the 
wood centre, splashed on the back with strongly gauged cement and sand to form a 
good key, and the concrete put in behind, so that when the wood centering is removed 
a finished surface remains. The boards can also be used for partitions, ceilings, 

linings, etc. 

Full particulars regarding these sheets, etc., can be obtained from Jos. Robinson 
and Co., Ltd., London, agents for the Carlisle Plaster and Cement Co., Ltd., Carlisle 
ChamlxTs, 10, Crooms Hill, Greenwich. 





EVERY INCH 
A MIXER 



THE 

VICTORIA 

CONCRETE MIXER 

(That's the way 
^^^|to dischargee 
concrete 



Write for Catalogue 
No. 29 and learn how 
the mixing is done. 

T. L SMITH Co 

13 VICTORIA STREET, S.W, 



360 



Please mention lliis Journal 'when 'writing. 




(TJ H 



o -^ 



S H 



-A, 

<3 



CONCRETE 

AND 

COlSfSTRUCTlONAL ENGmEERlNG 



Volume IX. No. 6. LONDON, Jl'NE, 1914. 

ED nV RIAL NOTES. 



THE CONCRETE INSTITUTE. 
The Council's Annual Report, 1913-1914. 

TnK C(u;nL'il of the Concrete Institute have presented their Annual Report, and 
a summary thereof, witli copious extracts, will be found in another ccjlumn. 

The L.C.C. Reinforced Concrete Regulations. 

Hie first point to note in the report is a matter of congratulation — namely, 
tliat tlie Institute's Council and Committees have devoted a considerable amount 
of time to consider thorout^hly questions reg"arding- the London County Council's 
(ieneral Powers Bill of 1909 as far as it relates to reinforced concrete. W'hat- 
e\er may 1je the outcome of these deliberations there is not the least doubt that 
the work lias been done pain>takin^ly with tiie best of possible intentions, and 
the recommendations of the Institute ma}" be looked upon as an equitable 
compromise between those who wish to over-police reinforced concrete and 
those who wish reinforced concrete to ha\e little or no restriction. 

Work of Technical Committees. 

The second feature of the report is that some of the technical committees of 
the Institute have been doing" a fair amount of useful general work, and have 
before them further important matters for consideration. We onl}" hope that 
the consideration of some of these subjects will be accelerated, as the all too 
frequenc postponement of even a provisional solution of an important subject 
becomes wearisome. 

As to the work of the various committees, we are surprised to find that the 
Tests Standing- Committee propose nothing very definite as to tests, for it has 
now a small fund to draw upon — namely, a fund that was specifically ear-marked 
for testing- purposes and reading-room purposes, comprising money which was 
collected from the existing members who chose to increase their subscription 
with a view to assisting the Institute in this direction. 

The Proposed Examinations. 

The third feature is the constitution of an examination board and the 
arrangement of examinations. In principle, we are entirely against the Insti- 
tute being- recruited by examination and ha\"ing its membership in the future 
chiefly based thereon. To our mind, the \'ery last object of the Institute is to 
draw hard and fast lines and to have a kind of minor specialist examination 
of admittance. The Institute, to our mind, was primarih- intended to bring 

361 



THE CONCRETE INSTITUTE, [ CQNCBETEJ 

together the various chisses of professional men, and those interested in the 
great industries concerned who wish mutually to discuss matters appertaining 
to concrete and reinforced concrete nncl their constituents, and anything in the 
wav of examination at this stage, wilh the object of putting those who have 
passed an examination into a kind of superior class and those very useful 
members who happen to be at the head of their relative professions or industries 

but ha\e not been examined- -into a secondary class is unwise indeed. The 

scientist, the chemist, the arciiitect, are, apparently, according to the present 
programme of the Institute, to play " second hddle " to the young surveyor or 
engineer, who, bv dint of cramming, passes a certain examination, and like- 
wise the captains of industry, who have more actual knowledge, gained in the 
hard school of experience, than many a so-called professor. 

We should have had nothing against an examination for a diploma, indica- 
ing knowledge of concrete or reinforced concrete ; or, in other words, we have 
nothing against an examination that would encourage students and junior 
members of the various professions and industries concerned. But an examina- 
tion that is eventually to create a class difference in the Institute is, in our 
opinion, a very sad mistake, and entirely uncalled for in a young institution of 
this kind. It is no doubt due largely to those who believe in the value of what 
we consider are unnecessary initials, and we are afraid the Institute has done 
something to encourage a craving for these emblems of class distinction by 
so systematically describing its members as M.C.I. 's. Such a policy may bring 
in new members and funds, but it is nevertheless to be deprecated. 

As to the proposed examination itself, we will deal with that more closely 
at a later date. We think it goes too far. 

The "Reorganisation Muddle." 

The fourth point, conspicuous in the report, is what we would call for short 
the Institute's " reorganisation muddle." A party in the Council of the Insti- 
tute apparently wish to turn it into a minor institution for structural engineers, 
which is entirely divergent from the j3rimary object of this body. Another party 
in the Cfiuncil oi the Institute urges a sidtiis quo in the objects of the Institute, 
in its Memorandum of Association, and, above all, a retention of its existing 
title pure and simple, whilst they are prepared to make gradually progressive 
changes in the articles or rules as the needs of the Institute may require. 

We have already pointed to the fact that a new memorandum and a new 
set of articles uere a(tuall\' " formally" (sic) passed at two extraordinary general 
meetings, without the purpose or the scope of these changes being properly 
realised b\- the j)rincipal L(jn(l(Mi members and not realised at all by those in the 
provinces or :ii)roa(i. Aj)[)arenlly these changes were made in such an extraor- 
dinary fashion that lh( y u ( re of no legal \alue, for e\en the resolutions, we see, 
according to counsel's opinion (|Uol((l in the re])()rt, were improperly dralted. 
To put il fjuite plainlv, malerial clianges were attem])led wliich would have 
entirely altered th(; objects of the Instilute and whic^h would have led to the 
resignation of nearly half ils nieinbers, and these changes do not excn show 
the redeeming feature of being well con.^idei-ed and properl}' brought about in 
accordance willi the law of llie land. As to whal the C'ouncil pi-')|)i)ses to do 
mav be read in ihe rejiort. The C'ouncil now by w a}- of compromise — 

362 



c 



j,CONMPtlC"riONAl 
'v KNdlNKl.PlNd -- 



ANNUAL GENERAL MEETING. 



SUJ4J4CS1, lliai (illuM- the proposed chani^c of lli<- general scope of 
llu' Inslitulv .IS set out h\ the irxiscd Mcinoi'iinduni of .\ss(jci:iti.)n 
of .\o\ iMiil)i-i- last 1)1' p.issitl 1)\ luo furtlicr i-xlraordinary <4c-ncial meetings 
with sindi additional aim-ndim-nts in the articles as nia\- be recjuisite, or thai 
the i'hani^i's atleni])ted in \o\i'nil)cr — whieli, as a matter ol iact, do not le^all) 
■" hold water " at tlu> moiiu-iit he foi-mally rescinded. This comj^romise al le.ist 
shows that the oi)pi)ni'nts to tlu' chani^v are making- thenisL-hes felt, 

Ti) these extraordinary j^c-neral nieelin,^s, of course, the whole ol the 
niemhership will hi' called; hut, as the .\nnual Re|)()rl |)lainly slates, quite lu(j- 
ihirds of them li\e awa\ from London. 'Ihese members li\in^ out of L(jndon 
are, howe\ei-, disfranchised, as ihey have no right to \ote by proxy. The 
result will thus be that, e\en il the changes were again adopted by a London 
majorit\ , several hundred of the pro\incial and colonial members would oppose 
the change in Court, and we are ad\ ised that they would have a very good 
prospect of succeeding; in other words, to-day's impasse would be repeated. 

We would thus strongly urge the Institute's Council to go warily in press- 
ing for the proposed change. The society stands a fair chance of being ruined 
if it adopts the proposed Memorandum — there would be a large secession from 
its membership and an immediate cessation of its usefulness. On 
the other hand, if it will go steadily, quietly, keeping its old memorandum, 
objects and title- -only gradually changing the articles as modern require- 
ments may necessitate from time to time — it still has possibilities of getting back 
the prestige it enjoyed during the presidency of Sir Henr}' Tanner. 

\Vg have been in the closest possible touch with the provincial and colonial 
members. The\- resent the proposed changes, and they have no desire to be 
associated with an institute ha\ing other objects than the original 
ones — namely, to elucidate questions relating- to concrete and rein- 
forced concrete and their constituents only. They m.ay be interested in steel 
frame construction as used in conjunction with concrete, and in concrete as 
used in conjunction with steel frame construction ; but steel frame construction 
is perfectly well taken care of by that senior of all engineering societies, the 
Institution of Civil Engineers, and by its existing junior associations. Should 
an institution for structural engineers really be required (and we believe, as a 
matter of fact, there is some scheme for one on foot), let those who are desirous 
of promoting such an institution work out their own salvation. The Concrete 
Institute has a raison d'etre and a wide sex)pe, and this wide scope will sulhce 
for the next few decades at least. 

Generally. 

The last two years of the Institute's work hav-e, as we see from the records, 
led to a slight increase in the members. But it would almost seem that the 
Institute has been lately marking time in this respect. 

We observe there is a new class of Associate Members already given in 
the Annual Report, and also a class of Associates, although of course neither of 
these classes actually exists at the moment, owing to the impasse referred to 
above. In students there has certainly been progress ; and this we attribute to 
the educational talent of the Institute's secretary. 

363 



THE CONCRETE INSTITUTE. 



[CDNCBETEl 



In l<jctLii"c work the curric uluni of the Institute lias been proHfic and tlie 
subjects chosen frequently of considerable interest. 

To repeat, ho\\e\er, the leading" feature of the Institute for the last year 
was the work done in trying- to get the London Reinforced Concrete Regulations 
put on to a sound looting", and certain other Committee work. 

Unfortunately, however, the good work has been largely discounted by loss 
of prestige, by dissension within the Institute and within its Council. 

If the new president can now by great tact and courtesy, by going slow 
in a.n\- question of change and by quietly improving" the administration retain what 
is to-da\' left of the Institute's prestige, he will do well and merit the thanks of 
the membership and of the nation. On the other hand, if he presses any personal 
views or predilections as to the subordination of concrete and reinforced concrete 
by according- structural engineering a primary position in the Institute, we are 
afraid he may have to preside at the Institute's funeral. 

We have, however, reason to believe that Professor Adams may be spared 
such a misfortune if he hnds it possible to fulfil the assurance he gave at the 
annual general meeting — namely, that he would use every endeavour to act 
impartially. Further, one of the vice-presidents, who Is so strongly opposed 
to the proposed change; in the original objects of the Institute, and who has 
some three hundred members with him, threw out a suggestion for com- 
promise that may bear fruit, as the President Indicated that he was not dis- 
inclined to further such changes In the rules of the Institute as w^ould give the 
provincial and the colonial member a sa}' in such important matters as are now 
before that b(jdy. 

If the opponents of the proposed changes achieve the withdrawal of what 
to them is an obnoxious revision of the Memorandum of Association and obtain 
a proper franchise for the entire membership, the}-, on their part, ought to be 
read}- to assist in llie modernisation of the Articles, for they would then ha\e 
achieved their j;rimar}- end of retaining the objects and titlt; of the Institute and 
have gl\en ex'ery member a propL'r say in the development of this Institution. 

Hut, unfortunate!}', the tension wilhin the Concrete Institute is such, that 
if the President repeats the blunder of glxing' offencx' to a large section of the 
membership — as he apparently did in his speech at the Institute's recent annual 
dinner — he may find an immediate secession of another groujD of members who 
strongly resent an}' tendency towards class distinction and may no longer care 
to be associated wi'h this body in an\- form. His remarks at this dinner have 
opened up fresh sources '.i'i dissension which il will not be eas\- to smooth over. 
We trust, however, that this new source of troul)le may also l)e eventually 
overcfjme. 

OUR CONCRETE COTTAGE COMPETITION. 

Every endea\-(jur is being ni.ide b} the Assessors to ccjmplete tlielr work In 
judging the drawings s( iil iji lor llie above (M)m])etition, so as to enable us to 
announce the resuh of same in our jul\' number. 

Xo fewer than 245 designs ha\e been senl in. 



364 



E 



tt3N."^ri?nc-nc;NAi: 



H.M. NEW STATIONERY OFFICE. 




H.M. NEW STATIONERY ^ 
OFFICE. 

By ALBERT LAKEMAN, MSA. 



' In our /.iniurv issue of last yejr toe ivere able to publish an article on this building in 
its earlier stages. The follo'wing article deals mainly ivith the superstructure. — ED. 




REINFORCED CONCRETE CONSTRUCTION. 

Thk descrij^tiun i;i\(.'n in the previous notes (k';ilt almost entircl}- with llrj 
general plan of the building's, the steel gantries which were employed during 
the erection of the work, and the foundation details generally. Owing to the 
whole of the superstructure being constructed with reinforced concrete, some 
notes on this part of the scheme should be of interest, and although there is 
naturally a great deal of repetition in such a large structure, there are features 
which are somewhat out of the ordinary run of every-day construction. One of 
the chief of these is provided by the arched beams which carry the building over 

n 



1 I I -L-IV r \ T± 




Fig. 1. Cross Section. 
H.M. New Stationery Office. 

Bazon Street and connect the warehouse and office portions. This connecting 
portion is about 40 ft. wide, and the distance between the two main buildings 
is 2y ft. 6 in., the height extending for three floors, viz., the first, second, and 
third, giving a total of 31 ft. above the first floor level. The external walls are 
of concrete, having a minimum thickness of 4 in., and the arched beams occur 
under these walls below the first floor level, as shown in the drawing illustrated 
in Fig. 2. They have a minimum depth of 2 ft. at the centre, which increases 
to 6 ft. at the springing points, the thickness being 12 in. The reinforcement 
consists of six rods on the soffit at the centre, and three of these are bent up 
towards the top, commencing at a point about 7 ft. from the centre line on 
B 36s 



ALBERT LAKEMAN. 



[CDNCRETEJ 




i CONMPIKTIONAU 
A usif.lNKtJJiNt. ^J 



II. M. NEW STATIONERY OFFICE. 



o-u-h side and ihr ir.nainino time rontinuc In :. line rMn.cnlnr with the soll.t, 
./„,1 ;„-,. ,-';,nir(l ^^v\\ dou n )nl,. ihc snpi>nnin- nicnilurs ;,1 the ends ol the span. 




Stirrups are provided throughout the length at varying distances apart, as 

shown on the drawing. A horizontal string course i8 in. deep with a 

B2 367 



ALBERT LAKEMAN. 



[CDNCBETEJ 




6 in. projection is formed at the 
top of this beam, and this is also 
constructed of reinforced con- 
crete. The remainder of the 
wall is constructed with con- 
crete, reinforced with horizontal 
and vertical bars, the piers be- 
tween the windows acting- as 
stiff eners to the horizontal por- 
tions, which are designed as 
deep wall beams, with twO' rods 
in the lower surface. These 
wall beams extend below the 
floor level for a distance of 
about 2 ft. , and as they take the 
ends of the floor beams they are 
increased tO' 6 in. in thickness 
for this portion. Short stirrups 

. . are provided with these main 
% a reinforcing rods, and in addi- 
i^ g tion the vertical rods are bent 
^ ^ round them, thus .anchoring 

5 5 S them to the mass of concrete 

^ o 

2 H above. The outer ends of the 
» c ** 
.2 w secondary roof beams are car- 

J^ > I ried by wall beams 3 ft. 4 in. 






deep, these being formed by 
;t 2 carrying up the parapets tO' the 
£ external walls for a height of 
I ft. 9 in. above the roof level. 
Tlicy also ha\e a thickness of 
b in., and the reinforcement 
consists of two rods in the 
lower and one in the upper sur- 
face, with vertical rods at 6 in. 
centres bent around both sets. 
The floors of this con- 
necting building are divided up 
into three bays by main beams 
24 in. deep and 8 in. wide, witli 
six bars as reinforcement in tiie 
tensional area, and each ol 
these lias a compression flange 
() ft. wide and 6 in. thick, 
whereas tlie remainder of the 
slabs are only 3.], in. tliick. The 
secondary Ix'ams are spaced at 



368 



i 



fONMPt)t"riaNAi. 



H.M. NEW STATIONERY OFFICE. 




Fifi. 5. Detail of Beam Reinforcement. 
H.M. New Stationery Office. 



5 ft 6 in. centres, .md tlu'si' \va\v a dcptli ol 12 in. and a tliickncss of 4 in., 
willi two bars \\\ ilir lower surfarc as rcinforccnuMil. 

I lu' nK)f is carried 1)> a similar syst<'ni, l)ut tlu- l)canis and slabs arc all 
rcdnccd in pr<)i)<)ili<)n to the h)ad to be carried, tliese beinj.,^ 100 lb. for the 
lloors and 05 lb. i)er stjuare fool for the roof, in addition to the (Ic.'kI weight of 
the malerials cmplovi'd. Stirrups are j)ro- 
vided in ail the beams, and tlu'se are 
kinked to cli]) the main reinlorcinj^ bars 
tightly. 

The front wall of the main building to 
Stamford Street is an excellent examj)]e of 
an external reinforced concrete wall, and 
here the window openings are about 10 ft. 
wide and h ft. high, with piers between 
3 ft. 2 in. wide. The minimum thickness 
which occurs over the w indow s between the 
piers is 6 in., and the reinforcement in these 
portions is provided by horizontal bars in 
the centre of the thickness and vertical bars 
in both outer and inner surfaces. The piers 
generally are i ft. 3 in. thick, and they arc 

reinforced with six \'ertical rods, one being placed at each corner and <me in 
the centre in each surface, with links connecting the whole of the rods. The 
ends of the horizontal rods in the w'all slabs are carried well into the pier, and 
are lapped for a length of 18 in. Additional rods are also placed around the 
window openings, and all bars coming against these at right angles are hooked 
over them, and thus the whole of the reinforcement is well tied together. All 
projecting mouldings are formed in the concrete, and the reinforcement is varied 
to suit this by turning out the bars as required, this occurring more especially 
at the top of the building, where a large cornice and the caps to the pilasters 
are introduced. There is some interesting work at this point, and the design 
of the reinforcement exhibits considerable skill in the manner in which it is 
applied to the various members. 

As stated in the previous article, the columns are spaced generally in rows 
20 ft. 6 in. apart at intervals of 15 ft. 2 in., and thus the main beams have a span of 
2oft. 6 in. and the secondary beams a span of 15 ft, 2 in. The size of the columns 
varies from 20 in. square to 24 in. square, with eight to twelve lines of vertical 
reinforcement well tied in all directions by links spaced at 8 in. centres. The 
floors have been calculated to carry a super load of 3 cwt. per square foot on 
the ground floor of the warehouse and 2^ cwt. on the upper floors, while in the 
office building the allowance is 100 lb. per square foot for all floors, and 65 lb. 
for the roofs. The slabs are only 3^ in. thick in the warehouse portion and 3 in. 
thick in the oitice portion. 

The main floors are desig-ncd as illustrated in Fis^s 5 and 7, which show a 
portion of a beam on the ground floor. This has a maximum depth of 2 ft. 2 in. 
from the top of the slab and thickness of 7 in., with six bars in the lower surface, 
four of which are turned up towards the ends of the spans to take the diagonal 

369 



ALBERT LAKEMAN. 



[CQNCKETEJ 



tension, and links arc provided which pass round these main bars and also 
around one small rod which is placed in the upper surface. Continuity rods are 
also placed in the upper surface where the beams pass over the columns, and 
liaunches are formed at the intersections. 




I'lil. I). \iew (,i liiiildiii^; (111 Waterloo Koad Side. 
II.M. Nkw Stationkry Oi-mce. 

The st;condary beams arc sjiaccd at 5-fl. ccnlrcs and these arc buiH up in 
a similar manner to the main l)eams. Tivey have a depth of iH in. and a thick- 
ness of 4 in. below th(; slab, with six bars as reinforcement in the tension area. 

']"he roof beams are spared in a similar m.iniiei- lo those oonstructed in the 
floors, but are of slif^htly smaller sections in c<)iise((uence of tlu' lighter k)ads 
to be carried. The whole of the reinforcement wIktc possible was l)uih up 
into (Y)mplete skeleton ff)rm before bcinj^- |)lac-cd in the moulds to ensure accuracy 
and effect economy. 

370 



' j,ClONMPlK-riaNAl, 
At-N(ilNt.t WIN(. -~. 



H.M. NEW STATIONIiRY OFFICE. 




I lie conci'dc (-1111)11 )\((1 lor the 
coluniiis u;is mixed uilli one j);irl oi 
I'oit 1.111(1 (-(iiicnl, one j);irt of s.iiul, .iiid 
1\\.) |);irls ol h.ill.ist, .iiul it will he seen 
lh;il lliis is iihkIi richer lli.in lli.it 
usually adopted. Tlu' object ol this 
mixture was to he ahlc to allow a 
greater stress per square inch on the 
material, and thus a less (|uantil\- was 
required and it is elaimed that economy 
was effected in this wa\'. 

The building has points of interest, 
inasmuch as it is a complete reinforced 
concrete structure throughout and the 
policy of H.M. Ofiice of Works in 
adopting- this material is commendable, 
as the question of fire-resistance is one 
of the utmost importance in a building 
of this class. The larg^e area and 
simplicity of the building- enabled a 
great deal of repetition to be made in 
the size of the mem.bers and thus the 
materials and centering- could be 
economically designed and used. 

ELECTRICAL INSTALLATION. 

The electrical installation includes 
the wiring- for lighting purposes and a 
separate direct current service for the 
lifts and other power requirements. 
The system of wiring commences at 
the main lighting and power switch- 
boards fixed at the east end of the 
basement ; and from the lig-hting" main 
board separate i9y 14 cables run to a 
central distribution board on each floor 
of the warehouse block, and from these 
7/16 sub-mains to the fuse-boards. 
The main cables are all paper insulated 
and lead-covered, whilst the sub-mains 
are rubber insulated run in galvanised 
tubing-. Generally speaking-, the whole 
of the distributing system of sub- 
circuits is also run in galvanised 
tubing-, which is placed on the surface 
of the concrete. Fixings are obtained 



^71 



ALBERT LAKEMAN. 



[CDNCBETD 



bN- means of iron dowels cemented In, and the cutting- away for these was 
executed hv the contractors for the electrical work, who installed a special 
motor-driven air-compressor which drives special pneumatic hammers. The 
concrete was found to be so hard that hand cutting- would have involved very 
considerable expense and labour. The lamps are distributed evenly over the 
whole of the warehouse portion, one being- provided for each bay of about 
15 ft. by 20 ft. and the boards and switches are g-rouped near the lift wells. 




The building- was desig-ned by, and is l)eing carried oul under the super- 
vision of, Mr. R. j. Allison, A. R. I. B..\. , one of the prin(-ij)al architects at H.M. 
Oliice of Works 

The g-eneral contractors for the building- are Messrs. Perry and Co., Ltd., 
of Bow, and th<; uhol<: of the reinforced concrete was <\'irried out on t lie Henne- 



y, CTONM VlIC- HON A L 



H.M. NEW STATIONERY OFFICE. 



hicilR" sNstcni lioin dcsii^ns |)i(|);ir((i 1)\ Messrs. Moiu licl ;in(l l*;irt luis. 'I h<- 
slt'clw ork lor tlic j^atitrics w.is supplied .iiid <reet4'd by Messrs. Drew, Hear, 
Perks and Co., I. id., lialtersea .Street W'Oil'Cs, and live reinloreiny; steel was 
supplied l)\Messrs. Doimaii, Ia>ni^ and Co., Lid., ol M i(ldi<'sl)r()uy h. The ballast 
v\as proeuri'd fioin the Mam i\i\ti- (irit Co., Rochester, and llu' <'lectrieal work is 
Ikmiij^" executed 1)\ Messrs. In K i- and i'l'eenian, of 20, New iiridf^e Street, i''..C., 
to the spe(Mrieat ion ol the C hiel i'",n<^in<'er to the OHiee of \\ Orks. The heating 
installation is heinj^ eanied out 1)\ .Messrs. Berry and .Sons, ol Westminster. 
I'he j)hotoi^raj)hs are those of .M'-ssrs- i flla Camera Co. 




Fig. 9. Arch and Buildins over j-iazon Street. 
H.M. New Stationery Office. 



373 



THE CONCRETE INSTITUTE. 



HDNCBETFJ 




ANNUAL GENERAL 
MEETING. 



The Fifth Annual General Meeting of the Concrete Institute took 
place on May 28th at Denison House, Vauxhall Bridge Road, S.W,, ivhen the Annual 
Report ivas put forward, Beloiv ive gi've a summary of the Report, — ED. 



A SUMMARY OF THE COUNCIL'S REPORT. 

Membership. — The Concrete Institute had on May 14th, 1914, 930 members, 
28 associate-members, 6 associates, 54 students, 5 special subscribers, and 16 honorary 
members, makini^ a total membership of 1,039. Of this total, 360 reside in London and 
its environs, 364 reside in the provinces, and 315 abroad. 

Classification of Members. — The decision of the Council, that when the total 
membership of all classes reached 1,000 an entrance fee of one f^uinea should be 
required of members joining thereafter, has been acted upon. Furthermore, at the 
beginning of the 19 13-14 session, a number of alterations were made in the Articles 
of .Association, with the approval of Extraordinary General Meetings. These 
alterations, in brief, extended the classification of the membership by the inclusion 
of classes of associate-members, associates, and graduates. No graduates have yet 
been admitted, pending the establishment of examinations. At the same time the 
subscription fee for full members has been raised to two guineas per annum. Associate- 
members and associates are each required to pay an entrance fee of one guinea and 
an annual subscription of one guinea. Students will continue to be admitted as at 
present, without an <'ntrance fee, though they will be required to pav a transfer fee 
of one guinea upon Ix'ing transferred from studentship to associate-membership. 

Finances. — In th<' j)revious annual report a surj)lus was reported, and attributed 
chiefly to the income- liaxing been increased abnormally by the collection of a number 
of subscri|)tions in arr<'ar. 'J'his year the position is reversed, in that a deficit of 
/.'i6f K,-. hkI. has been realised. 

Meetings. — 'Ihe number of meetings and i-ducational lectures given in the jjrevious 
.Session was larg<-r ihan in any (■ar]i<'r .Session. 

As the result of a ballol among members of Coimcil, the bionze m<>dal for the 
best Pajx-r read in the 1912-13 .Session has been awarded to Mr. .S. l>\lander, for his 
Pajx-r enlitUd " St* (I P'rauK- lUiildings in London." 

Early Copies of reapers. — It having been n'|)i-esenlc(l thai some members 
resident in \\m- prox'inces and abroad, or for otiiri- reasons iinable lo .attend the meetings, 
are desirous of receiving copies (jf jjaj)ers read at general meetings in advance 
of their publication in the Transaclions, the Council has tUxaded that in 
future nienii)ers may I'eceive regularb adwanee co|)ies of |)apers upon |)a\nient of 
5s. annually to cov( r the cost of postag-e, <'tc. The |)i'ivilcge of leceix'ing a<l\ance coj)i<'S 
will Ix- <',\t<'nd<'d without any ^iieh prixnienl t(; ;ill llios<' members who pa\' the new 
rate of >ubscrif)lion in lli^e menih; isliip cl.'is^ namcl\ , ^,'2 2s. |)cr annum. 

Meetings of Junior Members. in tln' past Session informal meetings of the 
junior m<int>ers of the Institut'C ha\c b<<n iiislilulMl. 'ihe mei'tings ha\'e so far han 

374 



.,toNMuiK-naN>u1 ANNUAL GENERAL MEETING. 



h-(KI tvn P^idav iwiiini^s, llu' lirsl luo t.ikin^ |)l;u<- on April ^^id .md M.i\ ist, i<ji4. 
'I'lu' altrndanci- .il lh<s<' iik'^cI iii^s has Ixcii \<i\ <ni()iiraj4inj4, and il is coiifHU-ntly 
<xi)<c-lvd ihat llu' in^vliiii^s will Ix- of j^i<'al <chuat ional assistant' to junior nuinlH-rs 
of iIk' InsiiiuU'. 

The Scope of the Institute. — In former ainuial ifpoiK r(f< r^'ncv has lH<-n nia<i<' 
to a " ConnnitU'-c ai)|)oint< il lo consicUr iIk' \\id'cn<<l scop^- of th<' ( 'on{i'<-l<' Instilulo," 
the titlo of this ( 'oiiiniilt<'<' Immmj^ sul)s<'qu<nll\ chanf^id to llu- " lnipr()v<'ni<:'nts 
('oniniill<H'." An ahstract of iIk- n-porl of tiu- ConimilU'o was aj)]Mnd<d lo lh<' report 
of the ("ounril for the kjii-i^ Session, in which it was stated that the (Committee was 
appoinl<d to l.aU<' <'nvri4<'lic strps lo di'vrlo]) tlK- struttuial <ni;in< ■ciin^ side of the 
widiMi€d scoix>, and that thi^' ('oniniilt<'0 had di'fmed for the purpose of the Institute 
that " Structural Knj4ineerin^ " was that hranch of engincx-'rinj^ which de.alt with the 
scientific desii^n, the construction, and the erection of structures of all kinds in any 
material. 'J'he Comniitte>e further defined " Structures " as bein<4 those constructions 
which are subject princij>ally to the laws of statics as opposed to those constructions 
which are subject to the laws of dynamics and kinematics, such as enj;jinos and 
machines. The Committee unanimously recomm<nd<d and the Council subsequently 
adopted their recommendation — that a sub-title should be add<'d to the Institute, so 
that the full title should be: "The Concrete Institute, an Institution for Structural 
Eniiineers, Architects, etc." 

Examinations for the Institute. — The C'ommittee also recomm<'nd<'d the institu- 
tion of examinations in structural i-ns^ineerinj;^. Accordingly, the Council, during the past 
Session, appointed an Examination Committee, which was subsequently (in December 
last) merged in a nucleus Examination Board. The Examination Board has compiled 
a syllabus and rules for the proposed examination, w hich are ajjpended to this rei)ort. 
It is proposed to hold the first examination next year. 

Alteration of the Institute's Articles. — The alterations to the Articles of 
Association, j)reviouslv referred to as having been carried at the Extraordinary General 
Meetings at the beginning of the Session, were made and adoj)ted at the suggestion 
of the Committee. 

Alteration of the Institute's Memorandum of Incorporation. — At the same time, 
proj^osals were put forward for the amendment of the Memorandum of Association, 
wherebv the enlarged scope would be more clearly defined, although the Committee 
had in their original re])ort stated their opinion that Clause 3 (i) of the present 
Memorandum did not limit the scope of the Institute to concrete and reinforced concrete, 
but that the clause enabled the Institute to deal with iron (including steel), bricks, 
gravel, sand, cements, and other structural materials, and their application. The 
amendment proposed to Clause 3 (i) was as follows, the words to be added being 
shown in black type, and the words to be omitted by italic tyi>e within square brackets : 

3. (i) To advance the knowledge of concrete and reinforced concrete and other 

materials employed in structural engineering, \thcir constituents,] and 

to direct attention to the uses to which these materials can be best 

applied. 

Consequential alterations were made in other paragraphs defining the objects of the 

Institute. Also, in addition, it was proposed to make an alteration consisting of 

adding the words " and Associate-Member " to the word " Member " in Clause 7, which 

defines the liabilities of the members, this alteration being suggested in view of the 

fact that a new class of associate-members was created by the alterations to the 

Articles. 

Action of the Board of Trade. — When the alterations were duly submitted to 
the Board of Trade, after their approval bv the general membership, the Institute was 

375 



THE CONCRETE INSTITUTE. [CONCBETEi 

required to give, and gave, an undertaking to apply to the Court for allowance of the 
alterations to the Memorandum. The Board of Trade raised certain objections however; 
in particular they objected that the addition of the words " and Associate-Member " was 
not an alteration of the objects of the Institute, which was the only alteration permissible 
in the Memorandum of Association, and that only with the approval of the Court, The 
Institute's counsel has similarly advised the Institute. The Board of Trade raised the 
further objection that, as the proposed alterations to the objects appeared to have the 
effect of extending the scope, they were of the opinion that the enlarged scope ought 
to be shown by an alteration in the title of the Institute. The Institute's counsel has 
also expressed the opinion that the resolution which was actually passed did not in 
terms refer to any alteration in the Memorandum of Association, the resolution using 
the words " New Regulations." Counsel expressed the opinion that the Court 
might verv well take this objection and refuse the order. 

Differences in the Council.— ^''^^^^^■ences have arisen in the Council as to what 
action the members should be recommended to take so as to put the matter in order 
before applying to the Court, and the Council has decided to place the following alterna- 
tive policies before a General Meeting of the Members before going into Court : — 

(a) To rescind the alterations to the Memorandum and revert to the original Memo- 
randum of Association with the necessary further alterations to the Articles 
to provide for Associate-Membership. 
{b) To rescind the alterations to the Memorandum of Association and to repass 
the same with such additional alterations as may be required to meet the 
objections of the Board of Trade. 
In connection with the second of these policies, the Council regret to find that a 
misunderstanding has arisen as to the intention of one paragraph out of twenty-five, 
namely, Clause 3 (2). If the second policy be agreed to, " concrete and reinforced 
concrete " will be specially and specifically mentioned in the aforesaid clause. 

Special meetings for the purpose of deciding between these policies will be convened 
at the beginning of next Session. 

Tlie Institute and the L.C.C. — The Council and Committees have been very 
much occupied in the past Session with technical matters. In previous Reports the 
action of the Institute has been recorded in respect to the Regulations made under the 
provision of Section 23 of the London County Council (General Powers) Act, 1909, with 
respect to the construction of buildings wholly or partly of r<'inforced concrete. The 
Institute made suggestions upon a draft which was submitted by the London County 
Council, and, subsequently made suggestions upon the first set of Regulations when 
issued h\- the London C-oiinty Council. These suggestions for (he amendment of the 
Regulations were sent to the Local (Government Board, and in June, i()i3, the London 
County Council rescinded their first set of Regulations and made new Regulations, 
which were the outcome of prolong<'d negotiations between technical advisers of the 
Council and the Local Gov<-rnni<-nt Boar<l. The statutory notice of the intention of 
th<; London Counly Council to apply to the Local Government Board for allovv^ance 
w,-i> duly given to the four Sori<-li<'S named in the Act, nauK-ly, the Royal Institute of 
British Architects, {\\<- Institution of ("ivil ICngin^'ers, the Surveyors' Institution, and 
the Concrete Institute. 'i"he second (and revised) R<'gulations thus came before the 
Societies for consideration with a vi<'vv to submitting furthe'- suggestions for amendment 
to the Local Government Board. It was found that, as a result of the n<>gotiations 
between the technical advisers of \h<- London County Council and th<' Local (iov<rn- 
m<nt Board, many drastic alterations had h<vn made to the first set of R<'gulations, 
and as the Building Acts Committ<''e of ihe L.C.C. r<'j)orte(l " in some instances they 
render the Regulations som<'what more onerous than lhos<; originally adopt<'d by the 
Council." The matt^-r is naturally one of <--xtr<m<- iniporlancy to th<' in<'mb<'rs of this 
376 



fa-00r«miUCTlCKAa 



ANNUAL GENERAL MEETING. 



Insliluli', luil iikkIv .is .iririMiiii^ |)r;i(lic-<' in London, hiii Ix'C.'iiis^' \]u- R^t^iilalions, w h<-n 
finallv ;i|)|)r()\((l, w ill pi oh.ibly be icfcii cd to l)\ niunici|);ili(i(s in promoting Rcf^ulations 
for ih<ii i<Np<(ii\<' lor.iliti<s. Tlu' ("ouniil ;nul tin- Standing C()inniilU'<'s, i.e., lli<- 
Siiiiirv Standinj^ ( "oniniitt<v, \hv K<Mnf()rc<d Concn-lt' Praclicv Stan<ling Coniniilt<'<-, 
the Pai lianKnlarv (\)iniiiitt<'<', :\n(] iIk- 'r<'sts .Standin«4 ('()niniill<'<', liav<', th<'r<.'for<', j^ixy-n 
iar<'ful (U^IaiUd consick-ralion to th<' r<'vis<'<l R<_t*ulations. 

riu> Institul<''s su}4^<sti()ns as to llu' anKMidnu-nt of the s<'cond s<'l of R<'^iilations 
\\<r<' s<Mit to the other t<'clinical soci<'ties, and the Institute has lx*en informed that 
thev have be<'n sui)port<(i in larife part by the Royal Institute of British Architects and 
bv the Surv<vors' ! n>titiiti()n. Th^' Institution of Civil I'Lnf*ine<:'rs informed the Insti- 
tute that thev had not made su,«4i^<'stions for amenduK-nt in detail. The Institute's 
sui^tfestions \v<'re finallv subniitt<'d to the L(x:al (iov<'rnnu'nl lioard in I)<-(<'inber last 
and are now und<T consideration by the technical advisers of the London County 
Council and the Local Government Board. 

The Institute's Committees have been so closely occupied with tl e L.C.C. Rcj^ula- 
tions that they liave not been able to do much other work, though they have a num!:)er 
of subjects in hand for consideration. The details of their work are given below. 

New Members of Council.— \n June, 1913, Major H. S. Rogers and Mr. Morgan 
E. Y<'atnian wvve co-oj^ted as Members of Council. 

President and Vice-Presidents, — In accordance with the Rules of the Institute 
one Vice-President has to retire every two years, in order of seniority. Accordingly, Mr. 
Edwin O. Sachs retired and was re-elected a Vice-President in November, 1913. 

Mr. E. P. Wells's term of office as President expiring in May, Professor Henry 
Adams was appointed President for the ensuing two years. The appointment of 
Professor Adams as President created a vacancy among the Vice-Presidents — who are 
required to number five — which the Council decided to fill by the appointment of Mr, 
H. D. Searles-Wood as \'ice-President. This will create a vacancy among the ordinary 
Members of Council. 

The following Members of Council have resigned during the past year : — Mr. E. J. 
Lovegrove and Mr. Henry Tanner. The foregoing vacancies among ordinary Members 
of Council have not yet been filled. 

The Late Mr. W. G. Kirkaldy. — The Council deeply regret to record the decease 
of Mr, William G, Kirkaldy, an esteemed Member of Council, Chairman of the Tests 
Standing Committee, and one of the representatives of the Concrete Institute on the 
Joint Committee on Reinforced Concrete conducted by the Royal Institute of British 
Architects. 

Finance and General Purposes Committee. — The Finance and General Purposes 
Committee has held regular meetings preliminary to each Council meeting, and the 
general results of their deliberations are contained in the foregoing pai ticulars of the 
Council's work for the year. 

Science Standing Committee. — In addition to considering the L.C.C. Regu- 
lations for Reinforced Concrete, the Science Standing Committee has been concerned 
with the revision of the Standard Notation for Structural Engineering Calculations, in 
view of the criticisms made at the General Meeting when the draft report on the matter 
was submitted. The finally revised notation will be issued shortly. In conjunction 
with the Reinforced Concrete Practice Standing Committee a Standard Specification 
for Reinforced Concrete work has been prepared in draft and will be submitted for 
discussion at a General Meeting next Session. 

The Science Standing Committee has the following further matters under 
consideration : — 

1. Standardisation of joints and connections in reinforced coacrete. 

2. Advice to Superintendents of reinforced concrete work. 

3. Amendment of the Standard Specification for Cement. 377 



THE CONCRETE INSTITUTE. [OQNCBETE] 

4. Co-ordination of the Standard Specification for structural steel of all kinds. 

5. The adhesion of and friction between concrete and steel. 

6. Reinforced concrete piles. 

7. The effect of sewage upon concrete. 

. 8. The effect of oils and fats on concrete. 

Reinforced Concrete Practice Standing Committee, — During the past Session 
the Reinforced Concrete Practice Standing Committee has met, in conjunction 
with the other Standing Committees and the Council, to consider the L.C.C. Regula- 
tions for Reinforced Concrete Work. The Committee has held joint meetings also 
with delegates of the Quantity Surveyors' Association, and with members of the Concrete 
Institute who are Quantity Surveyors by profession. Several meetings were held, as 
a result of which a draft report on a Standard Method of Measurement for Reinforced 
Concrete was submitted for discussion at a General Meeting. Since this meeting, the 
report has been considered by the National Federation of Building Trades Employers 
of Great Britain and Ireland and by the Institute of Builders, who have made sugges- 
tions for its amendment in certain particulars. Meetings will be subsequently convened 
to consider the various criticisms and steps taken to issue a final report in due course. 

The Committee has prepared, in conjunction with the Science Committee, a draft 
Standard Specification for Reinforced Concrete Work, as recorded above. 

The Reinforced Concrete Practice Standing Committee has the following further 
matters under consideration : — 

1. Advice to clerks of works, inspectors and foremen as to methods of properly executing 

concrete and reinforced concrete work and of preventing defects and failures. 

2. Regulations, recommendations of Joint Committees, and various methods of calculation 

in respect to the design of reinforced concrete and the like 

3. Forms and centering for reinforced concrete work. 

4. Standard concrete mixtures for general purposes. 

5. The use of cinder, ash, clinker, and breeze in concrete. 

6. Means of keeping reinforcements in place when concreting. 

7. Methods of making concrete watertight and of waterproofing concrete. 

Tests Standing Committee and Parliamentary Standing Committee. — 
The Tests Standing Committee and the Parliamentary Standing Committee have held 
joint meetings with the Council and the other Standing Committees, as previously 
mentioned. 

The Tests Standing Conimittte has the following matters under consideration : — 

1. The effect ui)on steel of the i)resence of sulphur in aggregates. 

2. The grading of aggregates. 

3. The expansion and deterioration of concrete due to changes of atmospheric temperature. 

4. The effect of the use of sodium silicate on the surface of concrete as affecting 

reinforcing metal. 

5. The erratic results obtaiiu-d by the Vicat needle in ascertaining the initial setting time 

of cement. 

6. The collection of data regarding the elastic moduli of concrete for stresses within 

working limits. 
Investigation Committee. — I he Investigation Committee has held meetings 

at which have been considered (a) the action of the Local GovernnK'nl Board in r<>s|K'ct 
to the periods allowed for th<- repayment of loans sanctioned by them to Local Aulhori- 
ti<'S for the construction of works of r<'inf(>rc(d ("oncr<'t<' ; and (h) rej)orts of failure's of 
reinforced concrete structures. In conneclion with the l.iller, a Standard Report Form 
for the us<' of observers of (k-fects and failtire-s has been diawn up. 

Joint Committee on Loads on Highway Bridges. — The Joint Committee 
on Loads on llii;li\vay l)ii<lg(s, (onduclcd by the ('oncrele Institute, has been engaged 
in the drafting of its rejjort, jnit it is not yet completed. It is expected that it will 
be ready for presentation for discussion at a Geiie'ral Mee'ting next Session. 

Attache'd to the; Re-jx^rt, in foiin of an Apj)e'ndix, we're' given the' Rtdes anil 
.Syllabus of the- proj)Osed Examination, and we- give- below particulars of same, as 
follows : — 
378 



[^'SmNS'im?^] ANNUAL GENERAL MEETING. 

APPENDIX. 
Rules of the Examination. 

TIk.' I*l\;iiiiiii;iti()n is dix'uh*! into two p.irls : 

Part I. Sci<ntilic (for ( Ir;i(hi;it<'shi|)), consists of wiitt^n |j;i|)<rs (1< ;ilin^ witli 

tli<' scii'mifu- basis of tin- sul)j<'tl. 
Pari 11. 'l\rhnical (for .\ssiH'ial<'-M<'nilH rshi|)), consists of \\iiit<n |)a|)4rs and 
vivd-vocc examinations, d<'alin<4 with tlu' ti'chnolo^y of tln' sul)j((t. 
riu' <'xaniination is lirld lialf-\i'aily in May and Octolwr. 

1. Tlio a},H> of till' ( andidalc at the date of examination is not restricted. 

2. A candidate n\a\ enter for Part 1. alone, and if successful lit- ma\ take Part II. at a 
subsequent I'^xaniinat ion. A candidate is not permitted to i)resent himself for Part II. unless 
he has passed Part 1., or one of the Pxaminations (see below) wliiili are accepted by the 
Council in lieu of Part 1. ; but a candidate may enter for Parts I. and II. together. 

In Part II. a candidate must enter for two at least of the subjects, one of whi(h must be 
Structural luigineering. The subject or subje<ts in which he is successful will be 
named on the Ortihcate. 

.^. The Examination is confined to Students and (iraduates of the Institute. 

4. Candidates exempted from Part I. may be registered as Cracluates without passing that 
part of the ICxamination, but no Certificate will be issued. 

5. Applications to be admitted to either or both parts of the Examination must be made 
on the prescribed form, must be received by the Secretary not later than one month before the 
date of the Examination, and must be accompanied by the necessary fee. 

6. The fee for either part of the Examination taken separately is j^i is. (One Cnunea). If 
the two parts are taken at one time the fee for the whole Examination is jCi iis. 6d. (One and 
a Half Guineas). 

7. Each applicant will be informed wdien he has been accepted as a candidate, after 
which the fee will be forfeited if he does not present himself at the Examination for which he 
has entered. 

8. Every candidate who qualifies in. or is exempted from Part I. of the Examination, 
will, on passing Part II., be granted a Certificate of having passed the Associate-Membership 
Examination. On passing Part I. a Certificate of having passed the Graduateship Examina- 
tion w-ill be granted. 

9. The fact of passing the Examination does not exempt a candidate from the other 
requirements for election in accordance with the Articles and By-laws of the Institute. 

10. Candidates are required to attend at the Examination Room fifteen minutes before the 
hour fixed for the first paper to be taken by them. 

11. Drawing and mathematical instruments, including slide-rules, may be used. The 
use of books will not be allowed in Part I., but in Part II. candidates may bring and use text- 
books and note-books. 

The following will be exempt from the requirement to sit for Part I. of the Examination. 
(a) Bachelor of Science. 
(d) Bachelor of Engineering. 

(c) Associate Member of the Institution of Civil Engineers (by examination). 

(d) Associate Member of the Institution of Mechanical Engineers (by examination). 

(e) Associate of the Royal Institute of British Architects (by examination). 
(/) The holder of a commission in the Royal Engineers. 

ig) The holder of such other degree or qualification as the Council may determine 
in specific cases. 

Syllabus of the Examination. 

Part I. (A) Compulsory .Subjfxts. 

I. Principles of Statics and Theory of Structures. — Forces acting on a rigid 
body; composition and resolution of forces; couples; moments of forces; conditions of 
equilibrium, with application to loaded structures. Graphical and analytical treatment 
of the foregoing. Centre of gravity ; specific gravity. 

Graphic and analytic methods for the calculation of bending moments, shearing 
forces, and the stresses in individual members of framed structures loaded at the joints ; 
reciprocal diagrams ; incomplete frames and redundant members ; buckling of struts ; 
effect of different end fastenings on their resistance; combined stresses; section 
modulus ; methods of dealing with statically indeterminate problems, as beams supported 
at three points, etc. ; travelling loads ; rigid and hinged arches ; stresses due to weight 
of structures ; theory of earth pressure and of foundations ; stability of masonrv and 
brickwork structures. 



THE CONCRETE INSTITUTE. KPNQ3E3^ 



2. Strength and Elasticity of Materials.— Fhyslcn] properties and elastic con- 
stants of cast iron, \vroui>ht irt)n, sleM;"!, timber, stone, concrete, cement, and other 
materials ; relation of stress and strain ; limit of elasticity ; yield-point ; Young's 
modulus ; coefficient of rigidity ; extension and lateral contraction ; resistance within the 
elastic limit in tension, compression, shear, and torsion ; strength and deflection in 
simple cases of bending; beams of uniform resistance; reinforced concrete beams. 

Ultimate strength with different modes of loading; plasticity and permanent set; 
working stress ; phenomena in an ordinary tensile test ; stress-strain diagrams ; suddenly 
applied and impulsive loads; resilience; fatigue of metals; effects of hardening, 
tempering, and annealing. 

Forms and arrangements of testing machines for tension, compression, torsion, and 
bending tests ; instruments for measuring extension, compression, and twist ; forms of 
test-pieces and arrangements for holding them ; methods of ordinary commercial testing ; 
percentage of elongation and contraction of area ; test conditions in specifications for 
the principal materials of construction. 

Part I. (B) Selective Subjects. 

Two of the following subjects must be taken in addition to the compulsory 
subjects : — 

3. Chemistry. — Constitution of matter; chemical elements; Dalton's atomic 
theorv ; Newland's law of octaves ; Mendeleeff 's law of periodicity ; modes of chemical 
action ; atomicity ; analysis and synthesis ; composition of materials employed in 
structural engineering. 

4. Physics. (Note : A candidate taking this subject must be prepared to answer 
questions in three of the five sections.) 

Sound. — Nature of sound; pitch, intensity, and timbre; transmitting media; velocity 
of sound; sound waves; vibrating strings, plates, and membranes; resonance; inter- 
ference ; reflection and absorption of sound. 

Light. — Theories of Light ; transmitting medium ; velocity of light ; solar spectrum ; 
laws of reflection ; ])hotometry ; candle-power ; candle-feet ; absorption of light ; colour ; 
polarised light ; action of lenses ; telescope and microscope. 

Heai.— Sensible and latent heat ; thermometers ; pyrometers ; effect of change of 
temperature in solids, liquids, and gases; transfer of heat; radiation; conduction and 
convection; relative conductivity; thermal units; Joule's equivalent; thermal capacity; 
specific heat; combustion. 

Magnetism. — Magnets; magnetic phenomena; magnetic field; polarity; the 
mariner's compass; magnetic meridian; deviation and declination of the compass; 
inclination or dip; induction; galvanometers. 

Electricity. — Static and voltaic electricity; induction; conductors; electro-negative 
and electro-positive elements; electrolysis; lightning; system of electrical transmission; 
electrical units; measureni<nt of <k'Ctrical work; Ohm's law; principles of arc and 
incandescent lighting. 

5. Hydraulics. — Pressure on surfaces; centre of pressure; strength and stability 
of structur<s supporting water pressure; laws of fluid friction; impact of water on 
surfaces ; storage of wat<'r and construction of reservoirs. 

6. Geology. — Classification of rocks; succession of strata in aqueous formations; 
explanation of geological terms ; glacial drift ; conditions of deposition in fresh and 
sea water; denudation; disintegration and chemical decomposition of rocks; method 
of dealing with bad ground for <'ngine<'ring works. 

7. Geodesy, — 'f'h<- th<'ory, structur<', and a<ljustm<nt of th<' j)rincipal surveying 
and levelling instrum<-nts, and the- princij)k's of their <'mj)loym<'nt under various con- 
ditions; land surveying; contouring; k-vi-lling and us<' of theodolit<'. 

Part II. Tkcmnkai.. 

Subject S nuist In- t.-ikcn 1)\ all candidat<\s, and at l<-ast one other subject. 

8. Structural Engineering (Generally L — M-.avvi'.ih of construction; loads— dead 
loads (dislribut<d and con(<ntrat<(i), liv<- loads (rolling and suddenly ap[)li<'d) ; IxMiding 
moments; resistance monK-nts; str<'ss<'s and strains; sh<'ar stresses; dell<H-tion ; 
secondary stresses; fatigue of metals; safety factors; wind i)r<'ssures ; standard sections 
of rolk'd st<-el ; j)rofX'rt)<-s of sections; girders rolhd sections (simpk' and compound), 

380 



r.^coNM-purrioNAiJ ANNUAL GENERAL MEETING. 



plato \v<'l) and laltic<' \\<1), trusMcl fi anu- ; j)illars, colimins, staiuliioiis, |)i<Ts and striils 
geiKTallv ; <'(T<Mitric loadini; ; fixity of <ii<ls; ; roofs symnu'trical and iinsynniK-lrical 
trusses; connortion of j^arts ; bridf<<'s <4ii(k'r, siisinnsion, rantilov<'r; archos — <'laslic 
rib, ri<:jid and briictnl, two and tlir<x> pivot<'<l ; nKthods of oroction ; testinj^ and inspecting 
materials of construction; <lT4'Ct of workshop processes on steel; mass retaininj^ walls 
and tluMr stabilit\ aj^ainst waUr ])r<ssur<' and <'arth pressure; pressur<-s in silos, bins, 
and liopiMMs. 

9. Reinforced Concrete Construction.— Cn^nern] principles; .idvant^a^es and dis- 
advantai^t>s of r<'inforc<'d concrete; niat<'rials of construction and their testinj^; nature 
and propertii's of materials for concrete; mixing concrete by hand and machine; effect 
of frost and precautions to obviate damage ; laying concrete ; testing actual concrete 
used; testing comj)let<xl structures; failures and causes; conij)arison of cost with other 
methods of construction; fir<-r<'sisting projx^rties ; causes affecting expansion and con- 
traction; surface finish, durability and maintenance; form work (centering, shuttering, 
strutting, moulds, etc.), precautions in fixing, order and periods of removal. 

Routine of designing; arrangement of roof and floor slabs, cross beams, main 
beams, and pillars; loads on floors; calculation of reinforcement for various parts; 
loads on foundations; rough estimates of cost; rules and regulations. 

10. Steel Frame Construction. — Order of procedure in designing ; external forces, 
wind, snow, etc. ; arrangement of roofs ; loads on floors ; arrangements of main and 
cross girders and stanchions ; caps and base plates ; grillages ; junctions ; erection ; brick 
and stone panels and casings; protection against fire; painting; rough estimates of 
cost ; rules and regulations. 

Candidates desirous of being examined in Masonry, Bridgework, or any other 
branch of Structural Engineering not specified above may be so examined subject 
to the approval of the Examination Board and upon notifying the Secretary at least 
six weeks beforehand. 

THE ANNUAL GENERAL MEETING. 
The Annual General Meeting of the Institute was held at Denison House, Vauxhall 
Bridge Road, S.W., with the outgoing President, Mr. E. P. Wells, J. P., in the chair. 
Unfortunately, there was only a very small attendance, and the discussion was thus 
kept within merely formal limits. We present a summary below of such discussion 
as there was, at the same time mentioning that the new President, Professor Henry 
Adams, M.Inst.C.E., was installed in the chair and took charge of the conclusion of 
the meeting. 

A special feature of the proceedings was the presentation of a medal to Mr. S, 
Bylander for his excellent paper, entitled " Steel Frame Buildings in London," which 
token he certainly merited. 

DISCUSSION. 

The President, in moving the adoption of the Report and Accounts, referred 
specially to the time devoted to the new Regulations upon Reinforced Concrete, which 
had occupied many hours. He believed the Regulations would become law in a very 
short time, and most of those interested in reinforced concrete, he was afraid, would 
find them very stringent indeed. There was a lot of other work to be carried on in 
the next 3^ear, which had had to be deferred owing to the amount of time that had 
been spent on these Regulations. 

Sir Henry Tanner, Kt., I.S.O., seconded the motion. The Council were to be 
congratulated on the increased amount of work they had done during the past year, 
and the number of papers which had been read must add much to the usefulness of 
the Institute. 

As to the financial situation, they had had some undue expenditure during the 
past year, but he was very glad to hear the President say that he thought, proceeding 
as they were, they should be in a better condition at the end of the next financial year. 

Mr. Edwin O. Sachs, F. R.S.Ed., did not w^ish to occupy their time on the annual 
report at a short formal meeting of that description, with a small quorum present. He 

c 381 



THE CONCRETE INSTITUTE. [CQNCBETE] 



congratulated the Institute on the excellent work w hich it had done in connection with 
the London County Council Reinforced Concrete Regulations. The work had been 
most studiously and carefully undertaken, and they hoped that there would be a 
successful issue to what had been done in that direction. It was a matter for 
congratulation that the papers had been more numerous and that some of them had 
been so interesting. 

The only point of criticism he wished to raise at the moment was in regard to 
what he might term the " Reorganisation " scheme. It struck him — and he spoke on 
behalf of a large number of members not resident in London — that the Council had 
been trying to go too fast, and that much trouble and friction could have been avoided 
by going slowly. There had been not only an admitted attempt to materially change 
the policy of the Institute, but that change had unfortunately been accompanied by, 
what he would term by courtes}', some most unfortunate errors or misunderstandings, 
and considerable muddling, which had not conduced to the prestige of the Institute. 

They all hoped, he was sure — and he thus emphasised it on behalf of a large 
number of country members — that the coming year would find some way out of these 
troubles, that compromise might be found to be the suitable way out, and that Professor 
Adams in his year of office might not have a troublous, but a pleasant time to look 
back upon when he ended the very difficult work of presiding over the meetings of 
the Concrete Institute. 

Mr. H. D. Searles-Wood, F.R.I.B.A., echoed Mr. Sachs' sentiment, and hoped 
there would be a little careful consideration, that they might resume their harmonious 
meetings again. 

The Chairman put the Resolution to the meeting, and it was unanimously adopted. 

The President then presented the bronze medal of the Institute to Mr. S. Bylander 
for the best paper that was read in the Session 1912-13. It was a most excellent 
paper. 

Mr. Bylander, in acknowledging the compliment, said he considered that the 
Concrete Institute was doing real good work for the engineering profession at large 
and reinforced concrete and steel-vv'ork in particular. 

The President said the last important business was for him to vacate the chair, 
after being in it for two years, and to instal Professor Henry Adams as the President 
for the ensuing two years. He desired to thank all the members for the extreme 
kindness they had shown him. In asking Professor Adams to take the chair, he hoped 
at the end of his term he would be able to announce an increase in the membership, 
and he trusted that the Institute would be more looked up to than it was at the 
present time. 

ProfeSoOR Adams, NLInst.C.E., then took the chair. He said that during his 
term of office he should use his best endeavours to serve them faithfully and impartially 
so long as he occupied the chair. Whatever his personal opinions might be upon any 
matter that came before the Institute, he should feel in duty bound, not only loyally to 
support, but to give effect, to the best of his ability, to the wishes of the majority; and 
he hoped that in a very short time they should be able to find some m<>thod by which 
the members all over the world would be able to have a voice in the management of 
the Institute. 

Mr. H. D. Skaki.es- Wood, i^\R.I. B.A., proposed a vote of thanks to the out- 
going President. 

Mr. E. Morgan Yeatman, M.A., in seconding the vote of thanks, said he hoped 
that in the position of past-President Mr. Wells would continiH' to gi\e the Institute 
his assistance on th<; Council. 

Tlif Resolution was carried by acclamation. 

Mr. Weij.s, in r<'liirning thanks, remarked that his best end<'avours would be at 
the service; of the Institute. 



382 



tVF-NCilNh I K'lNCi — 



PANAMA-PACIFIC EXPOSITION. 




m II I 








PANAMA - PACIFIC 
EXPOSITION. 

REDUCING THE 
FIRE HAZARD. 



Corner of Market anH Kearny Streets, San Francisco. 
PanamaPac'ikic Exposition 



By JOHN GEO. LEIGH. 



In the folloiving article it is 
shown hoiv concrete and rein- 
forced concrete ha've entered 
into the scheme of building for 
this Exhibition, primarily ivith 
a ■vietu to protection from fire. 
-ED, 



\'iHi\G with the marvellous resources of the country tributary to San Francisco 

are the advantages which have been conferred upon the city by geographical 

position and a splendid 

harbour. The commerce of 

the port has grown year by 

year, ever quickened by the 

opening of the Pacific, the 

discoveries in Alaska, the 

awakening of China and 

Japan, the acquisition by 

the United States of its 

island possessions, and, last \ 

but not least, by the certain 

completion of the Panama 

Canal. 

To celebrate this great 
event, and commemorate, 
unofficially, the city's resur- 
rection from the overwhelm- 
ing catastrophes of 1906, 
San Francisco is preparing 
a magnificent pageant, by 
which, coupled with a 
pledge to receive them with 
true Californian hospitality, 

C2 383 




Fig. 1. San Francisco and its Environs. 
Panama-Pacihc E.xposition. 



JOHN GEO. LEIGH. 



lOQNCBETEJ 




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it hopes to attract ten millions 
of people g-athered from all 
quarters of the world. Already 
visitors to San Francisco find 
it difficult to realise that eight 
years ago practically the entire 
city — excepting a residential 
district on the north-west and 
a fringe of houses in another 
corner — was little better than a 
mass of smouldering ruins. 
Hosts of friends rose up to 
succour it, giving its people 
hope and courage in the great, 
though seemingly impossible, 
work that lay before them. 
The result is a San Francisco 
even more beautiful and im- 
pressive than that of former 
days — a triumph, on the one 
hand, of honest wooden struc- 
tures and, on the other, of 
steel-frame and reinforced 
concrete. Rivalling as a 
monument to human skill and 
industry even the Panama 
Canal and International Ex- 
position, which, on the day 
it opens, will represent an 
aggregate expenditure of 
;£,' 1 0,000,000, will be the new- 
built city. 

In view of the proximity 
of the latter to large lumber- 
producing centres and the 
necessarily temporary nature 
of exhibition structures, the 
r^xposition authorities have 
endeavoured to eliminate so 
far as possible the general use 
of building materials such as 
steel, brick, stone and con- 
crete. Very conspicuous, how- 
ever, in their construction 
programme have loomed the 
questions of fire prevention 
and protection, and it is with 



T J, C'ON.M UMKTlONAl.l 
(tVt:N(.lNKl.RtN(i — i. 



PANAMA-PACIFIC EXPOSITION. 



tliis sidr of tlieir aiiivitiis ihal llic j)rcsi'iit arli(le will primarily deal. 
iMoin tlu" i^cneral i)laii <^f tin- grounds and l)uil(iin^s {Fi^. 2) it will he seen 
tiial llir main exiiibilioii paiaci's are IweKc in number. Of liiesc- eij^lit are 
C()inj)iised in a central i^innj), the walls of llu- various huildinj^s l)einj^- treated 





Fii 



(1) Palace of Machinery. (2) Palace of Horticulture. 
Panama-Pacific Exposition. 



with colonnades and otlier architectural features serving- as sides of the 
connecting- courts and avenues. Here and there, also, are placed 
various arches, towers, etc. The four remaining buildings form separatf' 
units, the Palaces of Macninery and of Fine Arts flanking- respectively the 
eastern and western extremities of the main group, while the Horticulture 

385 



JOHN GEO. LEIGH. 



[CQNCBET E] 



Palace and Festival Hall are >et in grardens to the south. In the centre of the 
south line ot tJie main yroup, frontino- the main entrance to the Exposition and 




Fig. 4. Palace of Fine Arts. 




3H6 



Fig. 5. The Tower Gate. 
l^ANA.M A- Pacific Exi'OSITION. 



on the north and south axis, 
is the Tower Gate {Fig. 5), 
a sculptured mass rising- to 
a heig"ht of 435 ft. — leading- 
from the Court of the 
Universe to the Court of 
Honour. That this g-rouping 
involves a g-reat fire risk is 
suiliciently evident from the 
fact that — with the exception 
of the Palace of Pine Arts, 
the Main Entrance lower, 
and the dome and dome 
substructure of ihe Palace 
of Horticulture — timber is 
exclusively employed in the 
frames, wall studding-, and 
slu-athing- of all the build- 
ings. To reduce tliis hazard 
the a u t h o r i t i e s have 
adopted several extra- 
ordinary measures a n d 
introduced not a lew 
noteworthy innovations in 
exhibition ])uilding- c o li- 
st met ion. A m o n g" tile 
foiincr mav be mentioned a 
fine (•(|uij)ment of fire-hg-ht- 
iiig- apparatus, su(^h as 
motor-driven lire engines, 
iiosi' wag-ons, and liook and 



J CONyilMKTlONAl. 
'v l.NdlNlA.K'INCi — 



PANAMA-PACIFIC EXPOSITION. 



lacklcr triic'ks; hij^li-pi cssiuc .in<l sccond.-iiy water syslciiis lliroii^lioiil llu' 
orounds and huildiiij^s, wilh static |)i cssiii is ol rcsiXMt i\ <-l\ ;^()o 11). aiul z^a 11). 
to <H) 11). piT s(|. iiu-li ; autoinatii- s|)i iiiklci s t hi oiii^hoiit llu- inlfiior ol the huild- 
inj^s, and open ( orncr spiii>l<K'i- hclxM'fn buildings ami on huildin^'-s facing each 
DtluM-; an automatic tiro alarm svslc-m, and such i)r()t<.'ct i\ c dc\ ici-s as wht'cl and 
liand chemical c\tiniL;uishcrs. I<:spcciallyvalual)]c, howcxcr, in the event of danger 
should he the coiicreti' " the walls " extending- from the ground to the tops 




Fif4. 6. Concrete " Fire Wall " —Palace of Education. 
Panama-Pacific Exposition. 

of the various parapets and — v, ith the object of preventing the spread of fire — 
subdividing- the main group of buildings into separate units. 

As indicated in Fig. 2, these walls are erected at the ends of structures 
connecting two buildings across an intervening court. They are composed of 
a 6-in. curtain wall reinforced by h in. sq. steel bars, i8 in. centres in both 
directions, and are supported by concrete spandrel beams, which, in turn, are 
supported by reinforced concrete columns, resting upon concrete caps supported 
on driven wooden piles. These " fire walls " are used in place of the regular con- 

387 



JOHN CEO. LEIGH. 



[QONCBKll IJ 



9uiiinj ani -I, 



2' . <• ijllilj »«' 




sicno* Tfuoaoa csirat 

Of BtAII. I 



StCTIOI t - t. 



tliritTtji :? TYfiotL coLunn 
sBOti'z kiiiroHCttfr. 

Sotlt HO. " Hi. 



mi i StCTIOI SHOtiia otrtii 
or rrnciL wtu HKiiroHOtuttt. 



Fifi. 7. Typical D<:tails <,f " Fire Wall - Construction. 
Panama-Pacific IIxhosition. 



388 



j,C0NMkMK-I10NAi; 
«VEJsl(.lNl-LWlN(. — . 



PANAMA-PACIFIC EXPOSITION. 



slriu t'u.n of limber coiiuniis, hy hykrill slicilliinj;- (j^rooved \v<j<k1 sheathiii^'^ lalli) 
:iiui |)l;islii-. In F/<,'. 7 will In- loiiiul some tyi)i(<'il details of this " fire wall 




Concrete " Fire Wall."" view showing form work. 
Panama-Pacific Exposition. 

construction, Figs. 8 and 9 beings photog-raphs of walls taken during- the progress 
of the work. 

A careful study of other types of fire-resisting- walls, such as brick self- 
supporting- walls and steel 
columns and beams with an 
8-in. brick or 6-in. concrete 
curtain wall, resulted in the 
selection of the above- 
mentioned type as the most 
economical in respect both 
of cost and speed of erec- 
tion. In this inquiry a con- 
crete wall 6 in. thick was 
considered equivalent for 
fire-resisting- purposes to an 
8 in. brick wall. The con- 
crete which has been used 
is a mixture of cement, 
sand, g-ravel, and blue trap 
rock, in the proportions of 
one part cement to six of 
aggreg-ate, the various 
parts of the latter being 

determined from time to time bv laboratory tests. The average cost of this 
wall, including curtain wall, beams and columns, and reinforcing steel and 
beams, has been approximately 2s. id. per sq. foot of surface. 

389 




Fig. 9. 



C nciet( " Fire Wall," view showing arrangement of reinforcing 
rods in concrete beam. 

Panama-Pacific Exposition. 



JOHN GEO. LEIGH. 



fOGlNCBETEJ 



Other fire-resisting- materials are being used in the construction of the 
Palace of Fine Arts [Fig. 4). Though isolated from the main g-roup of build- 
ing's, and therefore less liable to fire risks, this edifice has called for special 
protection, because of the anticipated valuable exhibits for which it has been 
prepared. The Fine Arts Palace, consequently, will be constructed with a 
steel frame, with walls and roof of cement plaster applied to an expanded metal 
lath, known as "Trussit," manufactured by the General Fireproofing- Com- 
pany, of New York and 
34 and 36, Gresham 
Street, London. T h e 
roof slab is approxi- 
mately 3 in. thick, w-hile 
the vertical walls have a 
thickness of 2^ in. The 
trussit, 24 gauge and 
I in. thick, is laid hori- 
zontally, and fastened to 
the steel frame (see 
■^ Fig. 10) by means of 
.° special wire clips placed 
2 5 in. on centres. The 
corrugations of the lath 
t, interlock at the ends, and 
* are fastened with 16- 
gauge tie wires at inter- 
; vals of 12 in. 
*- The cement plaster 

■; used consists of one part 
? Portland cement, three 
parts sand, and a small 
amount of hair, well 
tempered with lime mor- 
tar to set up hard and 
firm. The metal lath is 
supported temporarily on 
the inside face by 
studding, and the first 
coat of plaster is ap- 
plied to the fabric on the 
outside and llcjaled lo an even surface with a depth of at least -y in. over the 
extreme projections of the melal. After the first coat has set, the temporary 
studding is removeci and ihc ()|)posite si(k' of the melal j)lasteri'd as noted for 
the first coat, allouiiig for a total thickness of 2}, in., including the final 
plaster coat. I'his gives, in <lTcct, a reinforced wall of minimum thickness. 
C(jncrete, it may be explained, was not used, for the simple reason that the 
necessarily thicker wall w(>iild have been more costly. The final coat is of 




Fiji. 10. 



Trussit Wall and Roof Reinforcement. 
I^anama-Pacii IC Exposition. 



390 






PANAMA-PACIFIC EXPOSITION. 



hard \\;ill pla.sttT, coloiiri'd .'iiul si ipj^lcd in iinilalion of trav<Ttinc marble — 
tin- rliaiactfristir linish siiiracc on all the l'"xposili()ii j)ala(H's. 

A wall const iiution similar to that just di'srrilx'd will Ix- usfd for tlu- 
Main Iowim (iatc, f\(C|)l thai ihc j)lasUi- wall will he su])))oilcd 1)\ a woodiii 
insti'ad of a slci-l frame. in the (l<sis4n of this tower the type of const rud ion 
adopted is a steel striieture uhieli supports the timber framework of the lloors 
anil walls. This, although cv'rtainly not rirej)roof, ma\ be t<-rmed fire-resistin^'^, 
and an api)roaih to what is commonly known as "mill construction." 'I he 
jLjeneral frame of the walls i> buill up of h-in. l)y h-in. ])()sts, about Hit. on 
ci'ntres, with iiorixontal j^irts lo ft. centres, all with flush outside surfaces. To 




't:ficji J.J. 



Fig. 11. Typical Details of Transformer Vault Construction. 
Panama-Pacific Exposition. 



this framework is fastened the metal lath, the ribs of which run horizontally, 
and this in turn is attached to the supports with i.^-in. galvanised iron staples 

9 g-auge, 6 in. centres. The cement plaster is then applied as in the case of the 
Palace of Fine Arts. 

Alternate current will be distributed in conduits throughout the Exposition 
grounds at 4,000 volts, and will be stepped down, where required, to the 
adopted secondary voltages. For this purpose suitable fireproof transformer 
vaults, built of reinforced concrete throughout, are placed in all the main 
building-s in situations indicated in the g-eneral plan. Fig. 2. These vaults, of 
which typical details are shown in Fig. 11, are approximately 10 ft. by 10 ft. by 

10 ft. hig-h, having- walls reinforced with |-in. sq. bars, 18 in. on centres hori- 

39' 



JOHN GEO. LEIGH. 



ICDISCBETEi 



zontallv and vertically. In Fig. 12 are Illustrated two of the vaults in course of 
construction. 

Another use of concrete likely to be of interest to many readers may be 
noted in connection with the footing g-rillages. These generally, whether for 
pile or spread footings on earth, are of timber; elsewhere, however, and con- 
spicuously in the case of the Main Tower Gate, they are of concrete, reinforced 




li;^. \i. (Concrete- 'J'ransforiiier \aulis. 

(1) In the Mines and Mctallnrfiy Falace ; and (2) In the Varied Industries Palace. 

I'anama-Pacii'IC Exposition. 

with steel bars. The footings of this structure are twelve in number and of 
three different sizes, the largest — 14 ft. 6 in. by 17 fl. and 4 ft. 9 in. thick — 
capping a cluster of 42 wooden piles and supporting the cast-steel base of a 
tower leg. For a building of such magnitude it was deemed advisable to 
abandon the use of timber for grillage and adopt either a steel I beam grillage 
embedded in concrete or a reinforced concrete slal), and pre fere nee was given 
to the latter design because of its marked economy. 
392 



y^CONMPlK-riaNAl' 



PANAMA-PACIFIC EXPOSITION. 



raUiiii^ llu' l*'-\j)()slli()n as a whole, llurc can l)c' no (|U(sli()n that ihc firc- 
ri'sistinj^ (|uahlit's ol coiKM'ctt', cornljiiu-d willi its strcnj^th and clH-apncss when 
compared willi steel and brick const i net ion, ha\c ai)j)ealed with ^reat force to 




V\-A. 13. Court of Palms. 
Panama-Pacific Exposition. 



the authorities, and that in many minor directions also — e.g., as foundation 
for the wooden manholes for both the sewer and water systems, as backing 




Fig. 14. Court of the Four Seasons. 
Panama-Pacific Exposition. 



for the electric conduits, as manholes for the high pressure water system, and 
as steps and caps for balustrades — the material has been warmly welcomed. 

393 



JOHN GEO. LEIGH. 



CDNCBETEi 



Supplementary to the Festival Hall within the Exposition grounds proper, 
and for the purpose of accommodating- the various conventions, musical gather- 
ing's and other functions of kindred character which are being arranged for the 
coming- \ear, the Exposition Company is building at the junction of 
\'an Xess A\ enue and Market Street — in what is fitly described as the civic 
centre of San Francisco— a fireproof permanent Auditorium. This building, 
intended as a gift to the municipality and to form part of the new city planning 
scheme, covers an area of 113,438 sq. ft., and will have seating capacity for 
10,000 persons. The materials which are being used in construction are steel, 
stone, brick, terra cotta and concrete. The foundations and footings are of 
mass concrete, one part cemicnt, three parts sand, and four parts broken rock ; 
while all retaining and partition walls and corresponding foundations are of 
concrete of the proportions i :2 14, the whole being reinforced where required 
with deformed bars. The superstructure is a steel frame, fireproofed with 
concrete of a similar mix, the columns and steel beams, which are reinforced 
with Clinton welded fabric, 5 in. by 9 in. mesh, 12 and 13 wire, being so 
covered that there is a minimum of 2 in. of fire-proofing on all parts. The 
floors throughout are reinforced concrete slabs, spans up to 6 ft. 8 in. being 
3^ in. thick, reinforced with Clinton welded fabric, 3 in. by 16 in. mesh, 3 and 
8 wire, gi\ing a net area of "187 per foot of width. Slabs from 6 ft. 8 in. to 

8 ft. 8 in. are 4 in. thick, 

" " "" "■""•''■'■ and spans greater than 

8 ft. 8 in. are 4 in. thick, 
both being reinforced with 
2^ in. by 16 in. mesh, 3 
and 8 wire. The fabric in 
all cases is continuous over 
the tops of the floor beams. 
The basement and main 
floors under the Audi- 
torium, respectively 5^ in. 
and 7 in. thick, are laid 
directly upon the ground. 
The l)alcony construction, 
also of concrete, is banked 
up with G-in. walls and 
slabs, reinforced with de- 
formed bars. 

The grounds dedicated 
to the j)urposes of the Ex- 
position comprise 635 acres, 
divided into three sections 
and having about two miles 
of water front. In the 
centre are grouped in a 
rectangle, 2,900 ft. by 
1,437 ft., eight (A tlie great 




Y'lti,. 15. Court of Ahiiiidaiice. 
Fanama-Pacii-ic ICxrosiTioN. 



39+ 



(;,,ooN.sTm»cTioNAU PANAMA-PACIFIC EXPOSITION 

Ltv l-N(.lNI.l.VlN(i -^ J 

exhibition |);ilacH's, uilh ;i ('cnlral Court of lloiioiir, 500 ft. by 900 it., and, 
wt'st and (.•a^; ol thi^, \\id<- avt'nucs lorniiniL; sul)sidiarv courts. At one end 
ol the i^roup is tlie l'"inc Arts Talacc, a loui; curved building', with an area, 
inrhidini^ colonnadi- and iDtwnda, of 2o.:|,j^J5 s(|. ft., uliile at the other extremity 
is the .Machineiy P. dare. 'I'lie latter — 307 ft. by c)()7 ft. and 103 ft. in heig'ht — 
is probal)ly the lar»;-est tinil)er buildini^' e\er erected. Tlie foundations required 
i,(K)o j)iks, the t^irryin^^ capacity beini; taken at 20 tons per pile, and the limber 
in the buildinij;- itself amounts to al>out 7,600,000 ft., board measure. Flanking^ 
this i-< a building;', 250 It. b\ Soo It., intended lor automobile and m(jt(jr-<:ar 
exhibits; and westward, on cither side of the main entrance, are the Pakioe of 
Horticulture — constructed almost entirely of ^lass, 630 ft. by 300 ft., with a 
dome of 152 ft. diameter, risini^- to a heig-ht of 188 ft. — and the Festival Hall, 
with an area of 57,400 sq. ft. and seating capacity for about 3,000 persons. 
The main buildings ha\ e interior arched aisles, with a dome of 100 ft. at the 
centre, their heig^ht, as a general rule, beings 65 ft. to the cornice, 96 ft. to the 
ridg-e and 160 ft. to the top of the dome. 

East of the building's mentioned above are 65 acres devoted to amusements, 
usually known as " side shows," the concessions for which — fewer than 100 
out of a total of more than 6,000 applications — have, it is stated, been granted 
with " the most rig-id selectiveness," having- satisfied " a hig-h standard of 
propriety, g;ood taste and educational value, as well as effective fun-makings 
and entertainment." To the west are 65 acres assig^ned for the building's of 
foreig^n Governments, 45 acres for those of the States of the Union, 12 acres 
for the exhibits of the Federal Government, and larg-e areas for the live stock- 
exhibition building-s, racecourse, aviation field, drill gfrounds, etc. The two- 
story building- to be occupied by the exhibits of the State of California will be 
in what is called the " old mission " style, reminiscent of the Spanish occupa- 
tion, and will co\er a.pproximately 3,550 ft. by 675 ft. 

A quite unusual system has been adopted for the exterior lig-hting- of the 
buildings, the rows of incandescent lamps characteristic of the majority of 
recent exhibitions being- replaced by arc lamps and concealed searchlights so 
screened and directed as to flood with light the entire fronts. It is intended 
to open the Exposition on February 20th, when m.any of us hope to find the 
United Kingdom more w orthily represented than appears probable at the present 
moment, and to continue it until December 4th — an exceptional period due to 
the favourable climatic conditions ordinarily prevalent in the City of the Golden 
Gate. 

Warm acknowlcdg-ments are due from Coxcrete .and Coxstkuctional 
Engineering and the writer personally to the Exposition authorities — and 
particularly to Mr. Harris D. H. Connick and Mr. A. H. Markwart, respectively 
the Director and Assistant Director of Works — for much invaluable information 
and for placing- at their disposal a larg-e and interesting- selection of drawing-s, 
etc. ; and also to the H. S. Crocker Co., the official photog-raphers, for a variety 
of excellent photographs of San Francisco and its environs and of the 
Exposition itself. 



395 



EWART S. ANDREWS. 



[CDNCBETEJ 




PROBLEMS IN THE THEORY OF 
CONSTRUCTION. 

SLAB FORMULA FOR REIN- 
FORCED CONCRETE DESIGN. 



1^ 



By EWART S. ANDREWS, B.Sc.Eng. 

The question of Slab Formulae for Reinforced Concrete design is one ivhich claims 
considerable attention, and the article here published "will doubtless be of interest to those 
studying this important question, Folloiving upon this article is also a short article on a 
Bending Moment Problem, also by Mr, Andreivs, — ED, 



Very many mathematical investigations have been made from time to time by 
elasticians to determine the strength of slabs or plates supported along all four 
edges ; with the growth of reinforced concrete construction these investigations 
have received renewed attention. In the present article we propose to show how 
some such formulae can be derived in a simple manner and to compare such 
formulae with others which are in common use. The formula which is in most 
common use in this country is known as the Grashof-Rankine formula, and is the 
result of mathematical reasoning which is very difficult to follow, and experiments 
have not, we think, proved this formula to be much superior to others. 

Prof. Bach's theory is very much simpler to follow, and we will consider this 
first, restricting our consideration to uniformly distributed loads. This theory is, 
however, not in very common use because, in accordance with the usual manner 
in which its results are expressed, the reinforcement should be placed diagonally. 
We shall first show how this theory can be adapted to the ordinary case of 
reinforcement parallel to the sides of the slab. 

The fundamental assumption in liach's theory is that the reaction pressure 
of the slab along the four sides is constant. It is generally thought that this 
assumption is not quite correct and that the pressure is rather greater towards the 
centre of the sides. We will, therefore, deduce three sets of slab formulaL' based 
upon the following assumptions : — 

(l). Pressure upon supports uniform. 

(2). Pressure variation upon sides in accordance with a parabola. 

(3j. Pressure variation upon sides in accordance with a triangle. 

Case I. Uniform Pressure. 
This is Bach's Theory ; it is usually expressed as follows. Assuming that 
the diagonal sections are the weakest, consider the bending moment about the 
line AC, Fig. 1. 

Let p be the pressure per unit length along the supports and let W be the 
total uniformly distributed load and w its intensity per unit area. 

W 

'^^^" ^ = 2(l + bj 

^96 



(1) 



^2' CTONM kMK-|10NAl 



SLAB h'ORMULAl. 



The supporting" foivos oi i (actions niav hv taken as a forrc equal to pb actin^^ at 

\V 

y and one i^iual lo /»/ aelin^; al A ; the load on the A ABC- and acts at the 

centroid C ol tlu> ^. 



a 



The iieriiendic-ular distance of A' and V from AC are each - and the 

2 

perj^endicular distance of G fioni AC is . 

. ' . Taking moments about AC we have : 

T^ J- ' r^ pbXc ,pl^c W a 
bending moment = £5 = — ~ 1- ^' - ^ '^ 

2( 2 " 3 ^' 
Wa 



12 



(2) 



;\ 






Y 


B 


X 


\ 


1 

\ 

\ 
\ 

\ 

\ 


/ / 
/G 


X 




I 


r 


\ 

\ 

\ 
\ 
\ 

\ 
\ 
\ 








\ 

f 1 N 


c 








Y 



A 






Y 




3 


D' 
X 


, 


F' 


i 


< 

I 


E 
X 




i 


r 


r 






« — 


1 A' 

f i 





Fig. 



Fig. 2. 



But 



(tXAC = 2 area of A ABC = lb. 

lb 
• • <^ = ■^' 



B = 



12AC 

Wlb^ 
l2\7+b'' 



(3) 



397 



EWART S. ANDREWS. 



C QNCBETEJ 



Now this has to be resisted by the section AC, and if ch is the effective 
thickness or depth of the slab, we have 

B = i^.AC .ds' 
where />t. = resistance modulus. 
IX depends upon the percentage reinforcement and the working stresses 
adopted. For the "economic reinforcement" of '675 per cent, for c = 600 and 
^ = 16,000, />i = 95 ; for other percentages and stresses its value may be taken from 
the curves which are given in the text-books upon reinforced concrete. 

. ■ . In equation (3) 

Wlb 

\2AC- 

Wlb 



fx . ds'' = 



~\2{t'-\-h') 
_ wb' 

If we neglected the supports on the short sides we should have : 

Wb 



(4) 



where 



3 = 

8 

B = Moment of Resistance of section YY 
= fxds' . I 

J 2 Wb wb' 



(5) 



We could get result (4) from (5) by multiplying by 



3h 



'^V-'l 



being called a slab coefficient, which has the following values : — 



— , this quantity 



; 


Diagonal 




slab 


b 


coefficient. 


1 


•333 


1*25 


•407 


1*5 


•461 


175 


•502 


2 


*533 



This is the most convenient way of expressing Bach's theory for diagonal 
reinforcement. In general, however, the reinforcement is placed parallel to the 
two sides of the slab instead of diagonally ; we can therefore proceed as follows :— 

Bach Theory applied to Reinforcement Parallel to Sides of Slab. 

We can consider in a similar manner the strength of the section XX, Ftg. 2. 

1 ^ 
The reactions on the sides will have reactions at the mid-pomts ccjual to ^ 

at D and E and pb at Y. The load acts at the i)oint F. 
398 



i J, C10NM U»K riONAl ' 



SLAB I^^ORMUL.Ii 



Tlierefi^rc, tal<in^^ moincnls about tlu' liiu! A'A' we have 

/ \V I 

• I PI) • 

2 



«-^;"-;-'j-: 



= !^{2l \ h) 
4 

^ Wl{2h + l) _\Vl 

8(/ + />) 8 

Wbl 
8(/ + /)) 
Neglecting side support on long side, we should have : 

\Vl 



(6) 



B = 



8 



.'. Slab coefficient for XX =F/.= 



l + b I 



(7) 



+ 1 



Similarly, if we consider the strength of the section YY we should get : 

/ 1 



Slab coefficient for YY^Fi,^ 



l + b ^j^h 



{-) 



These results can be tabulated as follows : — 



/ 


Slab coefficients 


b 


Short section 


Long section 




XX 


YY 






F„ 


1 


•500 


•500 


V25 


•444 


•556 


1*5 


•400 


*600 


175 


'364 


'636 


2 


•333 


•667 



Case II. Pressure Variation according to Parabola. 

We have previously pointed out that there is reason to believe that in 
rectangular slabs the supporting pressure is greater towards the centres of the 
sides than towards the corners. 

We will now therefore assume the pressure to vary in the form of a parabola 
as shown in Fig- 3. We will take, as before, the total pressure on each side 
proportional to its length, so that the total pressure on each long side =Pl 

and that on each short side = Ps = 



2(/ + 6)" ^ ^" ^ ^^^^ ^^ 2{l + b) 

The pressure at the centre of each side is therefore 1'5 p, p being the value 
given in equation (1). The resultant pressure along AB will act at the point Y, 
while that on the half sides AX, BX will be at the centroids of the parabolas — i.e., 

— from X. 
16 



D 2 



399 



EWART S. AXDREWS. 



ICDNCBETEJ 



Therefore, taking moments about XX we have 



B=Ps 



I , 2Pl 3' U" I 



2 2 16 2 4 
Wbl , 3Wl- Wl 



4(Z + 6) ]6(l-hb) 8 



8{l + b)\ 4» 



(9) 





Fir . 3. 



Fig. 4, 



Neglecting side support, we have as before 



B=^^ 



.'. Slab coefficient for XX = Fi = 



I 



{H h) 
I 

46 
I 
b 



1- 

H 



Similarly, we get for W by reversing / and b 

b 



I 



Slab coefficient for YY = Fh 
400 



4 



l^b 



(10) 



J, cTONMvnc-ric»N(ATI 



SLAB FORMULAE. 



/ I 
These rcsulls c:u\ be t;ihul;iled ;is follows: — 



(11) 



/ 


Slab coefficients 


Short 


section 


A'X 


Long section YY 






t', 




F„ 


1 




'375 




•375 


V25 




•306 




'444 


r5 




'250 




•500 


175 




•205 




•545 


2 




•167 




'583 



Casi-: III. Pressure Variation according to Triangle. 

In this case we will assume the pressures to be even more concentrated at 
the centres than in the previous case, and assume the pressure distribution shown 
in Fig. 4. 

As before, we take total pressure on each long side =Pa= 77477 \ ^^^ ^^^^ 



on each short side = Ps = 



Wb 



2{l + b) 
Taking the side pressures as acting at the centroids of the triangles, we get : 

B=P . ^4-2. Pl. I _W,l_ 
'2 2 6 2*4 



Wbl 



wi- 



Wl 



^{l^-b) 12(/ + 6) 8 
8{l + b)( 3 i 



Wl 



8(/ + 6) 



i^-i) 



(12) 



. Slab coefficient for XX = Fi — 



l + b 



1 — 



1 + 



36 



I 



(13) 



Similarly, by reversing I and 6, slab coefficient for YY 

b 3 



= F/,= 



b 



14) 



401 



EWART S. ANDREWS. 



ICQNCBOEi 



These results can be tabulated as follows : — 



I 

b 


Sla 


lb coefficients 




Short section XX 


Long' 


section YY 




Fi 






f^i, 


1 


"333 






•333 


1-25 


"259 






'407 


rs 


'200 






•467 


175 


•151 






•515 


2 


•111 






•555 



The Use of Slab Formulae. 

We have, in the foregoing treatment, developed three sets of slab formulae, 
according to different assumptions of pressure distribution. Whichever of these 
is adopted, -and we think that the parabolic distribution is the best of the three» 
it should be remembered that the resulting calculations give only the average 
stresses across the section. A very simple rough way of allowing for this would 
be to divide the span into three equal parts and to space the rods in the centre 
portion twice as close as in the ends. The slab coefficients given by the Grashof- 
Rankine rules are, on the other hand, for maximum stresses only and relate 
strictly to central strips. If, therefore, we use formulae for average stresses we 
should remember that actually the stresses will be greatest at the centre ; as a 
rough approximation we might take the stress variation as parabolic. The 
reinforcement, therefore, should be spaced closer together at the centre than at 
the ends to allow for this variation in stress. 

For ease of comparison we will quote the values of the slab coefficients 
given by the Grashof-Rankine formulae. They are : — 



1 


Slab coefficients 


h 


Short section XX 


Long 


section YY 




Pj 




P, 


1 


•500 




'500 


r25 


•291 




"709 


r5 


'164 




•836 


175 


"096 




'904 


2 


"059 




'941 



If we use the Grashof-Rankine figures, the calculations give the reinforcement 
required at the centre only, so that there is some loss in economy if the same 
reinforcement is maintained throughout. 

We shall get these points more clear by a numerical example. 

Numerical ICxamimJ':. -A rectangular slab, 18 ft. long and 12 ft. wide, 
has to carry a uniformly distributed /oad of 200 lb. per sc/. f/ . Treating the 
ends as simply supported, and taking the stub as 5 ins. deep to iJic centre of 
reinforcement, find a suitable reinforcement in eit/ier direction, 

I IS 



In this case ' — ' — 15 
/; 12 



402 



n^fASiSr^ ^^^^^ I'ORMULAl. 



^ , ,. ,, , _U^/_(200X18X12)X(18X12) 
Free bending moinenl lor long span — - — 

-1,166,400 in. lb. 

, , , Wl (200X18X12)X(12X 12) 

I)(i. for short span — = 

8 8 

= 777,600 in. lb. 

(1) Parabolic Formula: F,= 250: F„ = '5Q0. 

.". B.M. for short span = 777,600 X '500. 

= 388,800 in. lb. (l) 

.•. B.M. for long span = 1,166,400 X "250. 

--291,600 in. lb. (2) 

Now for short span : ft= 18X 12 and (L = 5 

^ B ^ 388,800 _ 

^ bds- 18 X 12X5X5 

= 72 

Reference to a diagram shows that for ^ = 16,000 lbs. per sq. in., f^=72 for 

'5% reinforcement, so thac the necessary amount of steel parallel to the short 

., . '5X5X12X18 c-A 

side is =5 4 sq. in. 

100 

5'4 

Taking i in. bars of area '196 sq. in., we should require . = 28 say. 

196 

These could be arranged with the centre 12 at 6 in. centres, and the 
remaining 16 at 9 in. centres. 

For long span : 6 = 12X 12 and <i.s = 5 

.-. f.= ^91,600 _g^ 
12X12X5X5 
From our diagram we see that this is given' by about '57% reinforcement. 

. ' . Area of steel required parallel to the long side= 

= 4'1 sq. in. 

1 41 
. ' . Using 2 in. rods of area "196 sq. in., we shall require = 21 rods. 

* 196 
Say 9 rods at 5 in. centres at the centre, remainder at each side at 8 in. centres. 

(2) Grashof-Rankine Formula: 

F„ = '836 F; = '164 
. ' . B.M. for short span = 777,600 x '836. 

= 650,000 in. lb. nearly (3) 

.'. B.M. for long span = 1,166,400 x '164. 

= 191,000 in. lb. nearly (4) 

. r , 650,000 , ^ 

• • ^°' ^^^°^^ ^P^^ ^ ^18XT2^^T^^120 

This requires r42'^o reinforcement; it w^ould really be better to increase the 
depth. 

.-. Area of steel required = 1^ ^ X 5 X 12 X j8 ^ ^^. .^_ 

100 

• 433 



EWART S. ANDREWS. [CDNCBETE] 

191,000 ,, .,^,, .„ . 

for long span M ^ i2x 12X5X5 ^-^^' -^^^^^ 38% will give this. 

. ^ -38 X5X12X12 ^.^ 
. , Area required = r^r^r —27 sq. m. 

It will be seen that the Grashof-Rankine formula makes a greater difference 
between the relative reinforcements required in the two directions than does our 
suggested parabolic formula. 

A BENDING.MOMENT PROBLEM. 

" Tlie best position for the prop of a uniformly lo(^ded beam supported at 
one end and overhanging the prop at the other.'' 

In this problem no new principles are advanced, but the problem is not to be 
found in the text-books with which we are acquainted, and will probably be of 
interest to the students among our readers. 

A beam AB on span L is supported at one end A and overhangs the 
support C at the other end ; we wish to find, with a uniformly distributed load, 
the position of the support C which will be most economical — i.e., give the least 
bending-moment. 

If the length of the overhanging portion BC is h and the distance AC is Zi, the 
B.M. diagram will be as shown shaded in the figure ; the portion BxD is a parabola 
tangential at Bi and is the familiar diagram for a cantilever with a uniformly 

distributed load ; the portion AGCx is a parabola of height ^, the usual one for 

o 

a freely supported span AC ; and A\D is a straight line. 

The maximum positive B.M. will be given by KJ , which will be equal to 

-^ b her unit length 




404 



fj, CON.Vl PIK riONAl. 
L*Vl.N(.lNl.t.lMN(. — , 



A BENDING-MOMENT PROBLEM. 



^ - since llu' H.]\T. iM'lwecn the point 4, and the point /^ of contrallexure 

o 

will he llio same as for a freel\' supportcul beam of span A^E, and the maxinuim 

negative \akK is given by C\l). Our problem resolves itself into find the 

position of C to make .//\ or C|/) the least possible. 

Now, if you move tlie jjoint C to the left, C\D will increase and J\J will 

decrease, whereas if C moves to the right the converse happens. If, therefore, 

C\D = I\J, movement of C will increase one or the other, so that the least \ alue 

of either occurs when they are e(|ual. 

.p.. . p iU -- a)'- ^-hlr 

1 his gives - — — 

(S 2 

i.e., (ix-af^-Alr 
or (/,-a) = 2/, (1) 

Again, bv the propertv of the parabola 

This can be found by taking the B.M. at E for the span A\C\ ; also by 

similar A's. 

EF _AxE 



CD AiC^ 

i.e.. 



^p^^-x^L^ (3 



(4) 



Combining (2) and (3) we get : 

2 ^ ^ 2 h 

Ir 
or, ci — i- 

i\ 

Putting this result in (l) we get : 

i.e., /r-2/, l2-J{ = o (5) 

The solutio-n of this quadratic equation gives, taking the positive root : 

li 2 

••• l + - = ^'^^- = ^ = l + 2"414 = 3'414 
t-'i I'l '2 

or, /2 = ^^ i.e., h = '293L 

3 414 — 

In this case the maximum B.M. will be equal to 

Pl-f = P^(1293L)- ^ _^ 

2 2 23*3 

It w^ill be of some interest to compare this result with that which would 

occur if each end were overhung and the supports were placed so as to give the 

least B.M. for this condition. 

In this case the best condition is given when the overhang is '207L. This 

gives a maximum B.^I. equal to ^ ^ 207L) -^pL_ ^ which is half that 

2 46*6 ^^ ' 

for the previous case. 

+05 



REINFORCED CONCRETE IN BELGIUM. 



[QQNCRETEl 




BUILDING FOR THE BELL 

TELEPHONE MANUFACTURE 

ING COMPANY, AT ANTWERP, 

BELGIUM. 



:-l'/#///' 



An argument often brought forivard against the use of Reinforced Concrete for buildings 
ivhere elaborate machinery is needed is, that it is not suitable for this purpose. In the 
present example it is shoivn that any difficulties that may present themselves can be ivell 
oziercome, — ED, 

A LARGE building- was recently erected almost entirely in reinforced concrete for 
the Bell Telephone Manufacturing Company at Antwerp. 

The site of the new^ building, which is intended for a factory, is situated 
at Rue Diercxsens, Antwerp. This building is composed of a principal body 
having in plan the shape of a rectangle 72*93 m. in length and 1678 m. in 




Interior View of Machinery Room Ijei'ore Installation of Maciiincry. 

KlCrNI-OKCI.U CONCRETK BuiLOING TOR THE BkI.I, TkLKI'HONE M-ANi;i-ACTURING Co., AnTVVKIU'. 

width (243 ft. by 55 fl. 10 in.). On tlic long side of the Iniilding, lacing 
toward tlic (V)urlyard, ihc new building includes also a rectangular portion 
which will constitute the Ixgiiniing of a future extension. The dimensions of 
this portion are \()'yH m. long b)' X r>^ i^^- wide (35 ft. by 12 It.). 

The building is compf)se(l of a ground llooi' ])uilt ox'er a basement, four 

406 



r>, CONM PllCriONAl .1 
^tV KNdlNLl-I^lNd — J 



REINFORCED CONCRETE IN BELGIUM, 



upprr slorc'vs, ;in(l .1 H.il km.I. Hi.' I1<hmn .nc Mipp.rKd ))> lour lines of j/illars 
in ninlorcH'd coiurclc n;inul\ . l\\<. (inlr;il lines, one line f.-iciny tlu- slrcct :.ncl 
anollKT line l;i<in- llu- eourt>:ir(i ;il the b;iek ol the building-. 

The portion ol the future <-xlension is supported by five pill.-irs constructed 
r,uiru-ientl\ slron- lo support tlu' lo;id which will come upon iheni when the 
extension is <Tirt<-(l. 'ihe lour i>osts idonj-- the side of th<' adjoinin- building 
are also constructed in such a manner as to be stronj^ enough lo support the 
load of anv future extension which may take plac<- towards this adjoining 

buildini;'. 

The various lloors arc accessible by means of two staircases and two lifts. 
One of the staircases and one of the lifts is situated on the side of tlu- present 




\'iew of Macbinary Room installed. 
Reinforced Concrete Building for the Bell Telephone Manifactlring Co., Antwerp. 



factory, and the other staircase and lift are situated on the side of the future 
extension towards the courtyard. 

The pillars are resting- on foundations entirely in reinforced concrete, spread 
on the ground in such a manner as to produce a pressure not greater than 2 kg. 
per sq. m. (i ton iGh cwt. per sq. ft.)- 

It was originally intended to provide ordinary concrete foundations spread- 
ing the weight of the pillars over the ground at the rate of 3 kg. per sq. m. 
(2 tons 15 cwt. per sq. ft.]. After the g^round was excavated, however, to the 
level of the foundations, it was found that the subsoil was composed of fine 
sand mixed with clay, and the presence of water at this level had the effect of 
transforming the subsoil into more or less liquid mud. The difficult problem 

407 



REINFORCED CONCRETE IN BELGIUM. 



[CQNCCETEl 



of spreading heavy loads coming froni the pillars on to this very bad ground 
was salisfactorilv sohcd b\- the adoption of spread foundations in reinforced 
concrete. To facilitate the construction of these foundations it was necessary 
to surround them by means of wooden sheet piles, in order that the reinforced 
concrete work should be executed in the dry. These sheet piles were withdrawn 
after the foundation work was completed. 

The ground lloor is calculated for a superload of 2,200 kg. per sq. m. for 
the slab (4 cwt. per sq. ft.). The beams, however, are calculated for a super- 
load of 1,100 kg. per sq. m. (2 cwt. per sq. ft.). This different rate of loading 
on the beams and slabs was necessitated by the fact that the machinery is liable 
to be shifted to any portion of the floor slab, thereby creating concentrated 




J'^xterior View. 
Keisforcid Concrkte Building i-or the Bell Telephone Manufacturing Co.. Antwerp 



loads, 'ihc first, second, lliird, and fourth Hoors are all calculated for a suj>er- 
load of S50 kg. per sr|. m. (174 lb. per sc|. fl.). The flat roof has l)een calcu- 
lated \'>r a supcrlfjad of joo k'g. per sf|. m. (44 lb. |)er sq, ft.). Oxer and above 
the superloads indif ah d, ihc (l;\i(l weight of ihc constru(Mion and c-oinposition 
flofM'ing, weighing S4 kg. per s(|. m., lias been tal^cn into account b)r ihe 
grfjund, lirs!, sc( ond, lliird, and lourlh floors, and a la\'er of asphall weighing 
20 kg. per scj. rn. has 1)( ( n piMxidcd lor llic rool. 

Rivr r sand and hard br:)kcn slonc were used for ihc making of live con- 
crete. The malcrials wci'c mixed in ihe pi'opoil ions ol ;;oo k'g. ol ("cmcnt, 
'400 cu. m. of sand and '.Scjfj cii. m. ol gra\cl (ap|)i'oxima1cl\- 1, 2, 4 in parls). 
Concrth; tesl (aibes made wilh llicsc malcrials and wilh lliis mixture gave 
exc('ll( n1 results < )\ over 2,_|oo lb. per s(|. in. alter 1 w cut \-eighl da)'S. 

40S 



^^SKSSIS ^ REINFORCIiI) CONCRJiTH IN BELGIUM. 



Tlu' .stti'lw ;ii k is <nliril\ ci iinp: )sc(l ol inimd hars nl mild sled. 
Tlu' wall ol tlir IKml I'lcxalion lacing; \\\v slrccl and 11m- wall ol tlic hack 
i'U-\ati()n taciiii; llic lOiirlNard were const nictcd in brickwork, liaxiiii^ a lliick- 
iH'Ss of I it. () in. Iioni llic liist llo'nr lo lIic roof, and i ll. lo in. Ironi llic 
foundation'- to the lii st IIodi-. Tlic back wall o\ cilookinj; the court is laced 
with while enamelUd biicks for the i-ellcclion of lii^ht. '1 hcse brick walls are 
supported at each lloor b\ reiidoiced concr<'le lintels spreadiiii^ the loads on 
to the pillais. The walls at ea(di lloor, therefore, do not carr\ an\ load, and 
their thickni'ss is in accordance with the lU'li^ian regulations. 

/''>• ^ shows a i^eneial view of the elevation, which lias been desig-ned by 
the an-hiticl with the objet t of formiui^- a suitable continuation of the existing 
buildiui^'s. The two other \ iews show one of the floors previous to the fixing" 
of shaftini;- and niachiner\- and after the nia(-hiner\ has b'jen j)lace(l in position. 
/''/_<,'". 2 shows that there is no particular dilliculty in adapting ehiborate 
machinery to the fle)ors and pillars of a reinforced concrete factory, and, in 
spite of the heavy \ibration due to this machiner}-, scarcely any vibration is 
perceptible on the lluors themselves. Some of the launching machines resting 
directly upon the groimd floor weigh oxer nine tons each. 

A special method of fastening the machinery to the floor was adopted in 
order to prevent cutting holes in the composition floor and in the concrete. 
This process consisted in fastening the machines to the floor by means of pieces 
of felt about | in. thick dipped in a special c^ompound, which securely sticks the 
felt to the foot of the macliine and to the floor. Whilst this process does 
undoubtedly prevent, to a certain extent, the vibration of the machines from 
being transmitted to the floor, it was not adopted with this idea in view, and, 
apart from this, no other precautions, such as india-rubber sheeting or other 
material, have been taken to reduce the vibration. Needless to say, as usual 
in most factories, any of the machines are liable to be shifted from one place to 
another. This, however, can be done without any difticultv. 

The work was carried out under the supervision of Mr. G. A. Pennock, 
plant engineer. The general plans of the building were prepared by Mr. J. L. 
Hasse, architect of Antwerp, and the plans for the reinforced concrete work 
were executed by Messrs. Edmond Coignet, Ltd., of 20, \*ictoria Street, 
London, S.\\\, the entire contract being- carried out bv Messrs. G. Hargot and 
R. S'omers, of Antw erp. 



409 



THE CONCRETE INSTITUTE. 



[CONCRETE) 



S'teiifc^-iB 





j RECENT VIEWS ON 
I CONCRETE AND REIN- 
FORCED CONCRETE. II 



RECENT PAPERS & DISCUSSIONS. 

■B^^^— ^M^M^— — ■[■■■I M^— ^— 1^1——^— — ^—^ 



// is our intention to publish the Papers and Discussions presented before Technical 
Societies on matters relating to Concrete and Reinforced Concrete in a concise form, and 
in such a manner as to be easily a'vailable for reference purposes. 

The method lue are adopting, of di-viding the subjects into sections, is, loe belie've, a 
ne'w departure. — ED. 

THE CONCRETE INSTITUTE. 

THE DESIGN OF STEEL AND REINFORCED CON- 
CRETE PILLARS, WITH SPECIAL REFERENCE TO 
SECONDARY AND ACCIDENTAL STRESSES, 

By OSCAR FABER, B.Sc. 

The following is an abstract from a paper read before the Concrete Institute at 

their ^Hth Ordinary General Meeting. 

Jointed Construction. 
The author divided his paper into two sections. He first dealt with jointed 
construction, such as structural steel; and, secondly, with monolithic construction, 
such as reinforced concrete. In dealing with the case of a girder resting on the 
end of a steel stanchion, he stated that in several drawing ofBces he knew as a fact 
that the construction in such a case would be treated as centrally loaded. He proceeded 
to argue that this was not so, because, when a load was applied to the beam, 
it would deflect, and the end originally horizontal would assume a certain slope, and 
therefore one of two things would haj^pen — namely : (a) the end of the girder would 
lift, in which case the whole load would be carried on one flange, so causing eccentric 
loading; or {b) the column must be constrained to adapt itself to the slope of the girder, 
in which case a bending moment would be introduced into the stanchion by such 
constraint. 

In this way hv sliowrd that increases in strains of 140 and 480 per cent, respectively 
were obtainable. 

.Mr. P'aber took, secondly, for consideration the case of a girder resting on an 
angle bracket. He argued that if an ordinary bracket were used the action would 
not be very far from the face of the leg of the angle, since the horizontal leg of the 
angle would not be strong enough to resist the bending moment which would be 
produced in it. It followed, therefore, that, although the horizontal leg of the angle 
s<;rved a useful purpose in conner-ting ih-e girder to the stanchion, it must not be thought 
capable of su[)porting it. in effect, the construction became dangerous if the clearing 
between the face of the stanchion and the edge of the girder exceeded the thickness 
of the angle. 

'rh<' author su[)j)fjs( d tl^MV w<'r<^ few <'ngine<'rs present wlio would assert that this 
limiting ck-arance was n^'V<-r exce<'de(l in j)rartice, and an engineer had to carefully 
(■cjnsidf-r wh<dher it was desirable to •em])loy this type of bracket <>xcept for quite small 
reactions. He next considered a sliffi'm'd bracket. 

Confining attention (o rases where the workmanship was good, he assumed that 
the stiffening angles lind In-en machined or forged to fit the angle bracket perfectly, 
and that the bracket was initially horizontal. It followed that when the girder 
deflected there was a tendency for it to rest on the outer edge of the bracket, and ror 

410 



(^^Sr;i?i^SK^^ sr/i/iL .\a^/) rhinforced concrete pillars- 

vcrv sin.ill U);uls lluTi" w.is no douhl th;il this .uiually hapix-iu <1. As llic load 
iiUMcasrcl I he oiilir ccl^c ol ihe stiriciicrs yielded a|)i)reciably, and a j^roater area 
suppoiled llie load, the ri'actioii j^radiially appioaehin^ the face of the column. The 
author's i)ractice was lo make the web of the stilfeiiers sulficient in area to carry the 
r<'aetion under a uniloiin striss ul 7.], tons/in^. 

In calculatin<^ the resistance he ii^nor«'d a larj^e area of steel hi the llan^e of the 
stilT<'ners, and in iho wrtical k'l; of th<' anf^U.' brack<'t, because- {a) the clearance 
between the face of the stanchion and the end of the j^irder mij^ht be sufficient to 
prevent U-arinj^ on this steel; (/;) <\xn if it was not, this material could not be stressed 
appreciably until the stiffener webs are greatly overstressed. 

In any case the difference in cost between i^ood and bad brackets was an extremely 
small percentaj^e of the cost of the steelwork, and a smaller one of the cost of the 
buildinj^, and he declined to endan<^er the " ship " for what, in this case, mif^ht be 
fairlv described as a " ha'i)orth of tar." 

It has louLj been recoj^nised in good practice that the machining of the ends of 
stanchions was of the first importance. Yet there were at least two constructional 
works in London which, with a view to economy, omitted this item of workmanship, 
and were erecting considerable tonnages of stanchions with the ends left so that the 
upper tier had contact with the lower tier over the width of one plate only, the remainder 
of the section having varying clearances, often amounting to I in. The stress was still 
gaily calculated as uniformly distributed, and it had been explained to the author that 
" steel is a ductile material which would yield and flow " and perform other convenient 
antics, "until the stress was uniformly distributed." The effect of loading such a 
stanchion was to cause the plates to slide past one another, and to partly shear through 
the rivets. Even where stanchions are machined a careful engineer must satisfy 
himself that they were machined truly square. Architects should bear in mind also 
that, apart from the danger involved in these practices, the yielding of stanchions and 
brackets before they obtain their bearing involved unknown and unintended stresses 
on the stonework, and to the author's knowledge many a beautiful and costly facade 
and interior decorative work had been badly cracked by bad steelwork details and 
workmanship. 

From the consideration of Case i it would appear to follow that it was desirable 
to make these joints somewhat flexible, and occasionally this was so. If buildings 
were braced with diagonal braces he should say without question that stiffness of 
connections should be avoided. 

Unfortunately, such bracing had obvious objections, and the whole stiffness of 
practical buildings against wind lay in the stiffness between beams and stanchions. 

There was, therefore, no alternativ^e but to make the joints stiff and to make the 
necessary allowance for these secondary stresses in the design of stanchions. 

This might be onerous, both in requiring extra labour and an increase in material, 
but a conscientious engineer would grudge neither the one nor the other. 

Mr. Faber then dealt with the design on cleats. A common method of calculating 
the safe reaction of a cleat was to take it as the sum of the resistances of the rivets, 
the effect being to neglect the very appreciable stresses due to bending. 

Dealing with the bracing of pillars, Mr. Faber said that it was well known that 
pillars failed by buckling, and that their stress was to be determined with reference 
to their 1/g. This phenomenon was fairlv well understood, and there are sufficient 
experimental data available to make the design of pillars, with reference to what he 
might call primary buckling, a comparatively simple matter. The phenomenon to which 
he referred was that of secondary buckling, in which the pillar, instead of buckling as 
a whole, fails by the individual buckling of its component members. On this subject 
there appeared to be practically no experimental data and practically no formulae or 
rules for the guidance of a designer. The importance of this problem might be 
gathered from the fact that bad design in the matter of bracing in pillars was 
certainly responsible for the two greatest failures in recent years — the Quebec Bridge 
of iqoy and the gasholder in Hamburg. 

Monolithic Construction. 

Mr. Faber then proceeded to the second portion of his paper, treating of monolithic 
construction and the eccentricity of beam reactions on pillars therein. Whereas in 



ENGINEERS' SOCIETY OF PENNSYLVANIA. [CQNCBETEi 

steel construction the eccentricity was very definite and easily calculated with most 
common tvj3es of brackets, with reinforced concrete the eccentricity could only be 
calculated from considerations of elastic flexure, and the problem was a much more 
ditiicult one. 

There was, however, no lon<^er any excuse for claiming ambiguity, since the 
problem had been analysed very completely in " Reinforced Concrete Design," and 
numerical examples fully worked out. 

Ihe author took as an example the case of the outside column of a building, 
working it out in detail, showing very great increases in stress over the values as 
ordinarily calculated. If thoughts of eccentricity were banished, either from ignorance 
or under stress of competition, the actual maximum stress would have been 
1,300 lbs./in2. 

It is interesting to note that the outside pillar in good design did not suffer much 
reduction in size up through the last three tiers. This was in accordance with the 
best practice in steel-frame buildings. 

In conclusion, Mr. P'aber said that without suggesting for a moment that the 
engineering staffs of several constructional firms were not fully as eflficient as many 
consulting engineers, he did feel that the system of competitive designs and lump sum 
prices penalised good designing by such firms and secured the work to those respon- 
sible for the most risky design. The only correct system, in his opinion, was for 
the architect to entrust the design to an engineer who had his confidence and to invite 
tenders on the design which he prepared. The architect and building owner were 
then likelv to obtain a sound construction, and if they used their discretion in the choice 
of the engineer the work would not cost more than the minimum consistent with 
safetv. 



ENGINEERS' SOCIETY OF WESTERN PENNSYLVANIA. 

THE USE OF CONCRETE IN THE DESIGN OF MINE 

SHAFT LININGS. 

By WILLIAM ARCHIE WELDIN. 

The following is an abstract jrom a Paper read before the Engineers' Society of 
Western Pennsylvania; zve have reproduced those portions relating to the use 
of concrete in shaft linings. Our abstract is taken from the Proceedings of the 
Society, Vol. 2Q, No. 9. 

The primarv function of a shaft lining is, of course, to keep the excavation open, 
supporting the sides, and resisting any tendency to collapse. In the case of hoisting 
shafts, it is also required to safely guide and support the cages, stairways, pipes, etc. 
Partitions between hoisting and ventilating compartments, when required, are also 
a proper part of the lining. In certain cases the lining is required to exclude water. 

In their anxiety to be on the safe side, some advocate making the lining capable of 
resisting a static head equal to the full depth of the shaft ; giving for a reason, to quote 
from two recent articles : " Th<' concrete lining should exclude the w^ater entirely, rmd 
hence must Ix^ designed to bear v<'ry great pressure at considerable depth " — and — 
" The concrete should k<-('j) out live water complet<'ly, because weep ho'les are not 
desirable." 

This r^-quir^ment would result in linings of gr<'at thickness, heavily r<'inforced, 
and would require quite unusual expense in constructing shafts. In fact, shafts so 
proportioned would se^-m quite unreasonable lo one •experienced lin such works. It 
may be thought that all shafts should exclude th<' wat<'r so as to r<'du(e live cost of 
pumping. Even this consi<k'ration would call for .a lu-ad extending only to tlie first 
imjK-rvious stratum, reduced b\' th<' li\ (Ir.nilic gra(li<'nl of the malci'i.-il peivctrated. 
Usually, the surface water is the; only inflow of any consequence (Micounlered, and it 
is oftx-n no more than th<; requir<'nn'nts of fir<' prot'Cclion, sprinkling, etc., demand. 

Until within tlu- last ten N'^ears, shafts in Ameiic.-t were jflways lin<'(l with timlx'r. 
In the course of many years' expftrience with this material, designs practically 
identical in all essential features have been almcisl universally adopted. These 
designs nrc eminenth' satisfa(tf>r\', r^cpresfnling as ih^cy do th<' accunuilaled <'xjM'ri<'nce 

41 2 



1, CONMPIHTIONAI 



I)j^:si(;n oi- minii sjiai^'t linings. 



t)l m;m\ iiKii. I lii\\<\<i , \h<- risk of \'\yv, uns.itiNl.alorN lif<-, incKasiiij^ cost, .iiid 
ck-ciiasiiii^ tjLi;ilil\ ol loiiiin-crci;!! timb<r lia\o broiij^ht about lh<' substitution (jf 
cH)ncr<'t<' and oilui niat<'i ials, w hii^b r<'quir<' (lirf<'i<-nl tnatnu-nt , and oiwn up afr<sh thi- 
<'niir<' j)ri>bUni of tlrsij^n. 

It i> to be <\]H'Ct<Hl tliat t br woo(U'n lininj^s of sliafts for a modern mine will 
require renewal at least twice in tbe life of tlie mine. TIk.' eost of such renewal is 
of eour-e, \er\ much i;r<'al<'r than ih<' first cost. H<'sides the increas<' in co.->t oj 
timber w hich may 1h' <'\|)ei"t<'d in lh<' fuiure, th<' cost of r<'n<"wal of th<' old timl>er and 
substitution of the n<'w is hij^h, as the oixration must be carri<(l on )>iec<'meal and 
without inUrf<rinj^ with use of shaft. In s|)ite of j)recautions, th<' ofx-ration of ren-ewal 
of lininiLj has be^en known to r^esull in the collaj)se of th<' shaft, <'ntail)nj^ additional 
<'\|)i'nse. Of i-ours<\ such a sluil-down, wlK'tlKM' due to tir<' or oth-cr cause, means a 
lariie loss. The rix<'d <xi)<'ns<' of ke<'j)inif the workinj^s open and draim'd, and the 
salaries of a larj^o modern orj^anisation, mak<' a prolon<fed period of idU'ness little short 
of disastrous. 

TIk' pi-o])orlions of timb-er linings haw i^raduall)" come to be s-eltk'd by coinmon 
consi'nt. (\)mmercial siz<'s arbitrarily adopted ar<' used, of course, and these allow 
for decay and other defects as well as the sections necessary to r^esist external forces. 
Concrete Hninijs, on the other hand, are not limit<'d to conventional thicknesses and 
do not require large excess to provide for deterioration. An arbitrary thickness allowing 
sufficient space back of the form for good workmanship in djc^positing the concr^-te, 
should be shown in the design, and 12 ins. is suggested for this thickness. In sinking, 
all irregularities should be outside the neat line thus shown, so that the average 
thickness will be much greater than the minimum. In passing through clavs and 
friable shales, the scaling of the walls naturally increases the thickness, thus providing 
increased strength at such points. 

The Shape of a Shaft. 

The usual timber-lined shaft is rectangular in section, this being the outline best 
suited to the material. The recent introduction of concrete, however, a material suited 
to any shape, has thrown open the question as to what is the best outline of cross 
section. The subject '* Rectangular v. Circular Shafts " has occupied considerable 
space in current literature. The circular shape offers great advantages, and, for 
ventilation shafts, it is unquestionably the best shape to use. As the circle is the figure 
of least perimeter for a given area, it follows that a circular shaft will require the 
least material for lining and oppose the least frictional resistance to the air current of 
any possible shape. A further saving in material, particularly in cases where pressure 
is to be feared, is due to the fact that this shape is strongest in compression. There is 
an advantage in sinking, in that there is no tedious process of cutting out corners. 
In clay and other formations, which tend to fall into th-' excavation, there is a 
considerable saving due to the fact that the curved walls will stand much better than 
straic^ht ones. 




Fig. 1. 



+13 



ENGINEERS' SOCIETY OF PENNSYLVANIA. rCaNCBETE j 

In the case of ventilating shafts, there are no dit^kulties to offset these advantages. 
These same advantages are urged by many in favour of circular shafts for hoisting, 
and in Europe this is the favourite form. In the writer's opinion, however, there are 
sufficient reasons why the circular form should not be used in the United States, 
however successful it may be abroad. These reasons lie mainly with differences in the 
hoisting practice. On account of the underground conditions, the European mine 
car is small, being commonly limited to about ^ ton capacity, while in America cars 
of three and four tons are common. In Europe cages of 2, 3, or 4 decks are used when 
a large capacity is required, this practice being justified by the great depth of many of 
the shafts. 

Earlv designs of concrete shafts in America indicate an effort to compromise 
between circular and rectangular forms. Apparently a fear of excessive pressure 
prevented the use of straight lines, and there resulted various forms as shown in 
Fig. I. These arched forms are assumed to be stronger than rectangular shapes. 
This is true where water pressure is to be resisted in rock excavation. The fact seems 
to have been overlooked, however, that these arches can be depended on only when 
they have solid abutments. This is not usually the case, and where it is there is 
generally no need of their strength, as the walls of the excavation are self-supporting. 

In answer to the question : " What shape should be used for concrete-Iintd 
shafts? " the author said that ventilation shafts should be circular, and hoisting shafts 
rectangular. Where the requirements of ventilation necessitate an area greater than 
thr.t required for hoisting, such area should be enclosed by a rounded end. 

Drainage. 

As already mentioned, it has frequently been argued that all concrete linings should 
<^y elude water from the shaft. It is, however, very common practice to construct 
drainage systems behind the lining for the purpose of relieving the lining of all such 
hydrostatic pressure. 

Water rings are principally relied on to accomplish this result. These are cavities 
formed in some suitable stratum below the principal points of inflow, and extending 
entirely around the shaft. They are large enough for a man to crawl through, and 
doors are formed in the lining to give access to them. A recess is formed in the lining 
to intercept any seepage which may flow down the face of the lining and turn it into 
the ring. The bottom usually consists of a paved gutter having a strained outlet into 
a pipe extending down the shaft to the sump. This pipe is frequently connected to 
the fire or sprinkling lines of the mine. 

In concrete-lined shafts the water rings are generally supplemented by several 
vertical lines of farm drainage tile placed back of the lining. The joints are surrounded 
with broken stone to exclude the concrete. 

Materials for Linings. 

Besides concrete, already mentioned as a substitute for timber, brick and steel 
are occasionally used. Cast iron is well liked in P^urope, though little used in 
America. .Separately moulded concrete blocks and " timbers " have also been used. 

Concrete Blocks. 

Ne,ar]y all concrete linings are cast in place behind steel, or wood forms; but 
there have been some interesting cases of linings cast in whole, or in part, on the 
surface. 

A circular shaft 133 ft. d<ep and 13 ft. 4 in. diameter was recently sunk by the 
United Collieries of Chark-roi, B<lgium.* This lining consists of an inner layer of 
segmental concrete blocks, 30 in. high, yi in. thick, and 14 to the circle. B<'tween 
the blocks and the walls of tlw excavation, concrete is pour<'d, making a wall thickness 
of I ft. 7 ins. The blocks ar<' r<-inforoed and f)rovided with dow<'ls hoJding the succ<'s- 
sive rings in line and ring bolls proj<'(-ting into the concr<'te backing. Tlirough the 
latter is laced a zig-zag reinforcing of round rods which ties the blocks to the mass 
conrr^'t^-. If i^ st;i(<-fl that the fo^t wa^ $S.r)- p<T Jin^'.'il fool, ;in(l that this lining is 

* Tr.'inslatcd and abstrartcd from " Aiinales des Miiies He lielgique " by K. V. Buffet, 
published in Coa/ Age, June 2isf, 1013. 

4M 



r J, coN.vruurrioNAi 

L« V KNC.lNhr.KlNti — . 



DESIGN OF MINE SHAFT LININGS. 



<x\ua\ in stn'ii^tli to i>nc of m.i^onr\ ^j in. thick which would h.-iv<' cost $13.50. 
Mixture () j^ravtl, 3 .sand, 3 cmicnt. 

('()N( Kill'. I IMHKI-ilNG. 

S<>i\iraUl\ inould<d concn-U' iiuinhrrs, (U'sij^'nod to he substituU-d for fraiiK d 
timlxMs and <'r<'ct<'(l in tho sam<- way, hav<' also b<.'<'n iis<'d. Fig. 2 shows such a Hnin- 
as instalUxi in th<> incliiK'd shaft of th<" Ahnux'U Mininj^ Co., .Michij^an. The suco'ss 
of this installation and the well-known advantages of this type of structural construc- 
tion make it well worthy of serious consideration. Such structural concrete would 
se<'m to ofTor special ,idvantatjes for raj)id work. 'Vh<' iii< inl>ers can be moulded in 
advance of sinkini^, and if th<^ <M-ection jjlant is provid<d to i)rop<'rly handk* th<'s<" h<'avy 
pieces, there is no reason why such lining cannot Ix' i)laced almost as rai)idly as timber. 




Another necessary provision at the coping is a support for landing rails close to 
the cages. In the case of circular shafts this is usually provided by steel beams forming 
chords parallel to the cage ends. 

BUNTONS. 

The introduction of concrete for lining has brought forward an interesting variety 
of buntons, or cross members, for guide support. The first concrete shafts were 
provided with wooden buntons of the same section as were in use in timber linings. 
This was early recognised as begging the question, however, and the present various 
sections have been advanced as substitutes. Steel beams and channels suggested 
themselves, but experience with corrosion, in surface structures, naturally caused 
apprehension as to the life of these members. As explained elsewhere, this appre- 
hension is largely unfounded, but the fact remains that structural steel in such a 
situation cannot have the life of the concrete lining, and to that extent that design is 
inconsistent. 

Buntons of I-beams and H-beams of various sizes have been made, as well as 
beams and channels covered with concrete. While the writer has had no experience 
with the latter, he is inclined to fear that the life of the concrete covering, usually thin, 
will prove unsatisfactory, and would prefer a reinforced section. 

A curious example of conservatism is show^n in the fact that practically all designers 
have failed to realise that, as the standard timber lining breaks joints at the buntons, 
the latter are proportioned as struts, and also that the arbitrary spacing of rings in the 
timber lining is as much for convenience in handling the verticals and placing the 



E 2 



+ '5 



ENGINEERS SOCIETY OF PENNSYLVANIA, (OOMClJKl'Ki 

plank lagging as for needed strength ; whereas, in concrete, there is no such breaking 
of joints, and the end details usually adopted prevent any real strut action. 

Guides. 

Wooden guides are generally used, even in concrete shafts, long leaf }ello\v pine 
of the best grade obtainable is specified. The pieces are obtained as long as possible, 
and may be spliced by any of the well-known timber splices. A butt joint with a sub- 
stantial splice piece is preferable. The guide should be dapped over the buntons deep 
enough to give a safe bearing pressure on the dap when the action of the safety device 
brings on the maximum load. The size sanctioned by best practice is 6 by 8 ins. The 
longest diameter should be placed on the long diameter of the shaft in order to give 
large bearing to the safety device. Guides should be secured by countersunk through- 
bolts, not lag screws as are sometimes used. 

Stairways. 

Stairways are generally required by law, unless a second hoist is provided as an 
escape way. These are generally placed in a compartment of the hoist shaft. This is 
the most convenient arrangement, as the stairs communicate directly with the work- 
ings. Stairs are objectionable in air shafts on account of their resistance to the air 
current. The velocity of the air also makes travel on them highly inconvenient. 

Until recently, shaft stairs were generally built of wood. On account of fire risk 
this practice should be eliminated, particularly in concrete shafts. Many stairs have 
been built of structural steel. Here we encounter the same objections as are made 
to steel buntons, but it is hardly feasible to resort to few members of increased 
thickness. However, the cost of renewal do^es not include in this case the large extra 
charges mentioned in the case of lining renewal, and such renewal does not affect the 
output. 

The construction of light stairways in reinforc^td concrete is now well understood, 
and it is suggested that shaft stairs be built of this material. In ah but the shallowest 
shafts it is desirable to build the steps on rather a low pitch with frequent landings, 
on account of the great labour required to climb out of a de^p shaft; 7^ ins. rise and 
9^ ins. tread are recommended. 

Partitions. 

In g<neral it is desirable for large mines to sink a separate circular shaft for the 
sole purpose of conducting the ventilating current to the workings. This may be 
provided with a hoist operating between rope guides to serve as a second outlet or 
escape way, access to the shaft being provided by air locks at the top or bottom, or an 
escape way may be provided by some other outlet. Perhaps the best arrangement for 
large mines is a plain circular shaft for ventilation, a hoisting shaft for coal onlv, and 
a third shaft for hoisting men and materials. 

Howev<r, it is a common practice to combine in one shaft both hoisting and 
ventilating compartments. These must be separated by tight partitions. In the case 
of wood lining, the purpose was generally served by lining the air compartment all 
around with two layers of tongu<d and grooved flooring, having tar paper between. 
This same construction was at first ripp]i<(l to partitions in concrete shafts. A 
modification of this practice has been a(l()pl<<l by substituting a four-inch reinforc<"d 
concrete curtain for the second layer of sh<'alhing. This curtain extends into the 
concrete lining, filling a F-shaped groove cut by hand. At the Universal Mines of 
the Bunson Coal Co., built some years later, the wood sheathing was discarded and a 
five-inch reinforced concrete j^artition, stiffened with six-inch steel channel buntons 
every five fe<c^t, was cast after the lining was compk'te. It entered grooves cast in the 
lining. Such a partition is certainly mor<; consisl<'nt in a concr<'te shaft than any 
scheme involving larg<- quantities of wood. It is doubtful, however, if the use of 
structural sections as reinforcement in the stiffener is justified on account of the danger 
of separation f)n shrinkage of the concrete. Stiffcners cast in place, and reinforced 
with unit frames of rods, would probably be more satisfactory, and it is possibk' Ihat 
a wall of uniform thickness suflicient to give lh<' n quir<'(l stiffness would Iw more 
economical. 

416 



IS 



,cx:^NMyut'rioNAi, 



DESIGN OF MINE SHAFT LININGS. 



If thin sti(T<>n<"d jiartilions nro iis<'d, th<>y could probably b<' best fonii< d by plnstiT- 
in<^ r<ni<nl niorlar on on<' of lh<' S4'V<Tal pnUni combined nu-tal stuu and lalh fabrics. 

Sua IT Ho r TOM. 

ll is cusiomaiy lo build biick or concrete ai ches to 
protect the main hcadiiii^s at the foot of a shaft, and it 
is a simple matter of form construction to make a 
junction of these with the Iinin<:j. 

In a recent construction, the junction of the circular 
ventilatinf* shaft with the heading was made by crectinj.^ 
a half section of the shaft form in an inclined position 
forminj; a 45 dej^. elbow, thus reducini^ the resistance to 
the change in direction of the air current. 

A Suggestkl:) Design. 

The design shown in Fig. 3 is offered by way of 
sui^gestion. It is essential!} a rectangular shaft, the 
curved end being designed to include any area required 
for pipes and ventilating current. This area may varv 
from nothing to a large semi-circular compartment, 
according to conditions. 

In the case where no air way is required, if the 
modern practice of leading pump and compressed air lines 
down sei)arate boreholes is followed, the shaft may be 
rectangular, being symmetrical about the centre between Fig. 3. 

cagewa3's, and only long enough to include the end 
guides. The space between the cage and end wall should 

be ample to contain all wires and pipes required. If necessary, the end guides can be 
spaced a little away from the end walls lo allow more room for pipes. Pipes may be 
supported directly on the concrete walls, bv means O'f one of the several types of 
patented devices intended for attaching shafting, etc., to concrete buildings. 

Steel guides are suggested, supported directly on the shaft wall, using cast steel 
slippers attached to the corners of the cage at top and bottom. 

In order to facilitate the accurate lining up of these guides, which sliould be done 
with the help of a template, or gauge, in addition to the plumb lines, a wooden block 
is provided. 

If this use of guides at the cage corners be thought too much of an innovation, 
the guides may be secured directly to the straight end wall, thus eliminating one or 
two lines of buntons as the case mav be. 




4-17 



NEW WUHKS IN CONCRETE. 



[CONCRETE] 



NEW WORKS IN CONCRETE 

AT HOME AND ABROAD. 

Under this heading reliable information ivill be presented of neiv toorks in course oj 
construction or completed, and the examples selected ivill be from all parts of the world. 
It is not the intention to describe these 'works in detail, but rather to indicate their existence 
and illustrate their vrimar^ features, at the most explaining the idea -which served as a basis 
for the design. — ED. 



CONCRETE ON THE FARM. 

We have frequently given examples in this Journal of the utility of concrete for the 
farm and the estate, and its advantages have been shown not only in the United 
States, where concrete is so widely used in agricultural districts, but also in our own 
country, although over here a certain amount of reluctance still prevails to employ 
the material as frequently and freely as it might be used. It is nevertheless an im- 




View of Finished Mill. 
Concrete on the Farm. 



portant factor in h(l|)ing to solve the question of securing sanitary and healthy 
buildings in our agricultural districts. 

An int(;r(,*sting exanij^lc of the use of concrete in rural districts is here illustrated. 
The building has been erected on the farm of Messrs. E. W. Farrow and Son, of 
Spalding, Lincolnshire. In appearance the structure resembles a stone building, 
and it is to be used as a granary, warehouse, and grinding mill. In its erection 
concrete blocks, made on the site on a " Springfield " machine by Messrs. Goodwin, 
Brirsby and Co., of Leic<'St<'r, have l;ik<n th<' place of bricks, and it must 1k' admittxd 
that the result justifies th(; innovation. 

Hollow concrete blocks have been used, ballast and sand being used for the 
middle of the blocks, and for the (inc blocks a mixture of sand and cement in the 

418 



o, trJNM yUCTJONAD 



CONCRETE MILL CONSTRUCTION. 



proportion of 2.^ to i has been iis<h1, .iikI I lie coarser work lias been done witli a 
mixture of 5 of j^ravcl to 1 of ((MIKiiI. 

ThtMO is a 5-in. liollow in llir centre to ensuic clr\ness of the buildini^, and in 




Mill in course of construction. 




Mill in course of construction. 
Concrete on the Farm, 



order to effect economy the blocks are 16 in. long and 8 in. deep. These dimensions 
vary a little on some of the floors. 

The engine-house at the end of the building is 27 ft. bv 12 ft., whilst the rest of 
the building is 52 ft. by 27 ft. 

+ '9 



NEW WORKS IN CONCRETE. 



I CQNCBETEJ 



In addition to the four floors there is a tower on the building; the height of t!ie 
tower to the toj) of the vane being 60 ft. About 5,000 blocks were used for this 
building. 




View of Bridf^e in coi rse of construction. 




View of I'iiiished \'>Tii\iie. 

KkINFOKCI-.D CoNCRKTK HkIDOK at Tlll'KKTV. AUCIIENHI.AK. 

Wc would add, in eonclusion, that we are indebted to Messrs. E. W. Farrow 
and Son for our illustrations. 



420 



fe 



, CON.vryUCTIONAlJ 



REINFORCED CONCRETE BRIDGE. 



REINFORCED CONCRETE BRIDGE AT TIPIERTY. AUCHENBLAE. 

KINCARDINESHIRK. 

I Ills br'ul.'c has \nrn cicclcd l.\ lli»- Kiinaidint shire K(,;.(i lioard over a (laiii^crous 
foul on tlTr \\ci\\r W al.r al lii)!).!!) n. ai Auchciihla. . The Urid^c consisls of two 
si)aiix each of \i, IL, ;iiui tlu" width hclwccn the parapcK is K) ft. 6 in. I he 
macadamised roadwav is K. fl. wid.', has a -radi. iil of i in 70 in the l.-n.^th of the 
brid-c, and is ranicd by a slab S in. ihlck, suj. ported ^on two centre l)<;-'n)s 30^ in. 
di<'i') and 1 s in. widr, and two si<l 



Ik'P aiu 

rcinft)rci'd lrans\ crsely l)> j-ni. i()cl> 
at 5-in. centres. The centre lieams 
i-in. rods in conii)ression ; while ih( 
and three li-in rods in compression 



icanis _|S in. deep b\ I J ill. wid'i'. 'I h<' slab 1-. 
it 5-in. centres, and lon^itudinall\' by ^-\n. rods 
lave each eijLilit 1.1-in. rods in tension, and four 
side beams have each six li-in. rods in tension 
The shearin<4 reinforcement consists of slirriijjs 

The ]/ierced 
'I h;- whole 



of i^-in. rods in the centre beams, and of i^c-in. rods in the side beams, 
parapet is 4^ in. thick and is r<'inforc:d by ^in. vertic.d and hori/cnilal rods 
of the reinforcement consists of plain steel rods. 

The concrete for the reinforced work was composed of iS() lb. of cement to 4^ cu. fl. 




Reinforced Concrete Dome to New Synagogue, Fallowfield, Manchester. 

of sand and 6f cu. ft. of crushed ^ranite; but the actual proportions were slightly 
varied in the course of the work so as to secure a dense mixture. 

The pier, abutment, and wing walls are of plain concrete composed of 186 lb. of 
cement to 4^ cu. ft, of sand and gcu. ft. of H-in. gravel or broken stone. The founda- 
tions were carried down to rock at a depth of 6 to 7 ft. below the bed of the river. 

Gravel and sand for the plain concrete were obtained from the river bed at the 
site. For the reinforced work the aggregate consisted of f-in. to |-in. crushed granite 
with sand partly from the river bed and partly from a pit in the vicinity. 

The top surfaces of the slab and side beams were covered with a waterproof 
coating of asphalte | in. thick. The roadway is laid with tar macadam, and the toot- 
paths, formed by the tops of the side beams, are protected from the traffic by granite 
curbs. 

All external surfaces of the concrete were painted with cement grout. 

Four months after completion the bridge was tested by running on to each span 



42 1 



NEW WORKS IN CONCRETE. 



[CQNCBETEJ 



three road rollers of an aggregate weight of 53 tons. Under this load the deflection at 
the centre of each span was'rather less than 0*03 in. The beams were designed as 
simplv supported on the pier and abutments. 

The engineer for the work was Mr. George Gregory, Jun., C.E., of Stonehaven, 
whilst the contractor for the work was Mr. William Tawse, Torry, Aberdeen. The 
cost of the bridge, including the tar macadam roadway and granite curbs, was about 
;^7oo; in addidon about ";^35o was spent in diverting roads and forming new 
approaches. 

REINFORCED CONCRETE DOME FOR THE SOUTH MANCHESTER 

NEW SYNAGOGUE. 

Reinforced concrete construction is admirably adapted to the design of the_ dome^ of 
this buildino-. Two illustrations are given, one showing a section in detail, giving 





i^^g 








Jd-O' 



J 


S 




---;;^s^^ i 




I 


M^^'-'^'M • 




-sS^S 


L. 


b 


fj 



the general dimensions, and iIm: ollur an outside view of the finish<'d work. It will be 
seen that the dome is carried on four square concrete piers, which are continued to 
form four s<,-mi-circular arclK-s, and on the square made by these four arches a circular 
concrete beam is fornK-d, from which rises the shallow dom<', giving very satisfactorily 
the desired effect of an Eastern place of worshij). 

The architect was Mr. Jos. Sunlight, of Manchester. 

The reinforced concrete construction was carried out by Messrs. Richard Johnson, 
Claf)ham, and Morris, of Ix'ver Str<'<it, Manchester. 



422 



y,CONMyiK-riONAi: 
ti-KNOlT^JKl WINti- 



COiVCAVirZi FOR MARCONI STATIONS. 



CONCRETE BLOCKS FOR MARCONI WIRELESS STATIONS. 

TilK ;iccoiii|)anviii,i; illiislraliDn sliows lh<? ( Jov4rniiUMit M;ir<()ni Wireless Slation and 
Machine House, at Accra, ("lold Coast, West Africa. 'IIk' building is one of a number 
er<'il<'<l hv th<> C^rowii Ai^^'nts for th<' (^oloni<'S Public Works I )<|)arlnH lU in West Africa, 
and has been constructixl in " Wini^<'t BIocUs," 




Marconi Wireless Station built of "Winget" Blocks at Accra, West Africa. 



A NOVEL CONCRETE CIRCLE BLOCK CORN CRIB. 

The accompanying illustrations show a concrete circle block corn crib made with a 
special silo mould. It cures corn and heaps it to perfection, while the cost works out 
less than if built of lumber. 

It has great capacity at small expense, and is rat-proof and fire-resisting, and it 
costs practically nothing in maintenance or repair. It will be seen that this circular 
structure is built of large flange blocks, easy to place and reinforce. The flange on 
block carries reinforcing wires and projects out from the wall to form water liable over 
ventilated openings. Reinforced circle block walls have 20 per cent, ventilation, and 
the structure has a reinforced circle taper block self-supporting roof with ventilated 
cement block flue in centre of crib that exhausts in cupola at roof line. 

The roof and walls are watertight. In the construction of this concrete circle block 
corn crib 14-ft. silo moulds were used to make the blocks. The walls are 2^ in. thick 
and the roof is 2 in. thick. 

The corn crib has a foundation 8 in. wide by 7 in. deep, and is well reinforced. 
The floor is 2^ in. thick with woven reinforcement and extends over the foundation, 
so as to form part of it. The shallow foundation allows the structure and contents to 
come and go with the frost without damage. 

The first row of blocks are settled in the green concrete of floors. On the top of 



+ 23 



NEW WORKS IN CONCRETE. 



ICDNCBETE 



the third row of blccks a rat proof txtcnsion projicts out from the wall 3^ ins., and 
small wire mesh is placed on the inside of wall over openinii^s below extension to exclude 
vermin. A galvanised iron door is hun<;' on the gas pipe door frame which excludes 
the rats at this point, leaving no opening at which they can enter the crib. 




Fig. 1. Form of Mould used for Concrete Corn Crib. 

The roof is made of circle blocks 2 in. thick and tapered to suit the circle in 
which they are placed, and reinforced at the top to withstand the thrust from above. 
The cost of erecting this corn crib in America w^orked out at a total of $48.50; of this 
the roof is approximately one-third of the total cost. The weight of the roof is 4,100 lb., 





1^ 



/ 




, 1 5 8 k • • « • • *» « i ftfi» i.,j ^^ 

III Hi^^^f tillllllliii' 

www WTTttif,,,, 

• If fit iff 1 1 1 I ., 

"Tfi ffirfffifft' 

• it flwv fit III in f 



li til III mill 



f I ! 




Fl(,. 2. ViKW OF KkI.SIORCKD CfJNCKKIE CoKN CrIB NKAKI.V COM I'I.ETKl). 



the walls w'eighing 6,900 lb., and I he foundation and lloor aboul (),()()() lb., while the 
total weight of the 14-ft. crib is about 10 tons. 

'I'he drawing in Vig. i shows the form of mould us<'d in (-oiislructing this concr<'te 
corn crib as developed at Gr.and Ka[)i(ls, Iowa. 



424 



■ J, CON.M PIKllONAi: 



A COSCRHTJ^: ClUMNRY. 



A CONCRETE CHIMNEY AND SIGHT-SEEING TOWER AT DRESDEN. 

'I'liK (i<rin;in connclr <'hinin<\ .iiid sij4hl-sr<'in-4 l(>\\<r .it I)r<s<l(n i> ^<•■(•^ in ili<- .iccum- 
panviiii; pliDlOi^iMph. This arlislic roiuri-U' chiniiK'V in<;isiins ^j in. in Ik ii^hl. 'I h<' 
si,:4ht-s<'rinj.i platform is locaU'd at a lu'ij^hl of \2 ni. 

This tower was lonstriuird h\ M<'ssrs. A. I\iihn^i-h<if, jun., fornKrly I"'. W'ach- 
snuilh, of I )r<"-(i(n. 




A Concrete Chimney and Sight-Seeing Tower at Dresden. 



+ 25 



NEW BOOKS. 



ICDNCBFTFJ 



NEW BOOKS 

AT HOME AND ABROAD. 

A short summary of some of the leading books -which ha%>e appeared during the last feiu months. 



The Hydration of Portland Cement, Iron- 
Portland Cement, and Blast Furnace 
Slag. CDie Hudratation Von Portland 
cement, Eisen-porttandcement und Hochofen= 
scnlacken/i By Dr. Ferdinand Blumenthal. 

Cementverlag G.m.b H., Charlottenburf<, 1914. Price, 
1.75 Mark. 

This pamphlet gives a general account 
of the chemistry and physics of the setting 
of cements, and also a series of very in- 
teresting original experiments, in which 
microscopical examination is combined 
with the use of chemical reagents. This 
part of the subject is illustrated by means 
of photo-micrographs. The following are 
the principal conclusions :— 

Portland and iron-Portland cements 
yield the same products on hydration, 
namely : (a) hexagonal tables of tri- 
calcium aluminate ; (b) small needles of 
mono-calcium silicate ; (c) gelatinous 
mono-calcium silicate ; and (d) large hex- 
agonal crystals of calcium hydroxide of 
relatively little importance for the process. 
The setting of cement is a process of 
crystallisation, the crystals of aluminate 
and silicate becoming interlocked, whilst 
hardening is due to the formation of a 
gelatinous mass, which unites the crystals 
in the same way as glue. This process 
continues as long as lime, silica and water 
are available. Iron oxide can take part 
in the setting, forming ferrous silicate and 
tricalcium ferrite. Blast-furnace slags 
which contain a sufficient excess of lime 
yield the same products. 

The Influence of Moisture in the Air on the 
Volume of Cement Mortar. (Einfluss der 
Wasserdampftension der Lujt auf das 
Volumen des Cementmbrtels.) By Leopold 
Jesser. 

Cementverlag G.m.b.H., CharlotfenbuifJ, 1913. Price, 
I 50 Mark. 

This pamfjhiet describes the influence of 

ih" absorption of water in the form of 

vajjour bv mortars of different richness on 

th(-ir volume. It is shown that the volume 

of a mortar increases \\ ith the moist ness of 

the air and diminishes as it becomes 

drier. A mortar j)laced in air saturated 

with moisture undergoes a further, but 

relatively small, ex[)ansion wh"n placed in 

water. These changes have been followed 

quantitatively. They ar<' r<v<rsil)l<', 

except for a change which takes |)Iace in 

mortars which have onlv hardened for a 



short time. These properties are depen- 
dent on those of thp gelatinous mass which 
constitutes the greater part of the mortar. 
The thermal expansion of mortar also 
depends on its hygrometric condition. 
Some of these facts are of importance in 
connection with the behaviour of con- 
crete dams and containers, one part of 
which is in contact with water and the 
other with air, and the subject deserves 
attention. 

Handbook for Constructional Engineers in 
Reinforced Concrete. (Aide-M^moire de 
ring^nieur=Constructeur de "Beton Arm^.) 
By Jean Braive. 

Paris, 1914. H. Diinod & E. Pinat. 

The compiler of this volume has set him- 
self the task of compressing into less than 
400 pages the essential formulae and rules 
of the reinforced concrete engineer, 
together with a number of worked 
examples. Much of the material included 
is of a kind to be found in engineering 
pocket-books, such as tables of trigono- 
metrical functions, lists of densities, etc., 
together with rules of arithmetic and 
mensuration. This section is followed by 
very brief notes on cement, methods of 
testing, and special systems of reinforced 
concrete construction. Eighty pages are 
then occupied by the French official regula- 
tions, which are given in full. This 
section, which should be found very con- 
venient by workers in France, as a com- 
pact collection of official documents, is 
followed by a condensed treatise on the 
I)rincip.les of computation of reinforced 
concrete structures. It is to be noted that 
Professor Mesnager, in his preface to the 
book, dissents from the principle adopted 
in the computation of resistance to shear, 
insisting that the method generally em- 
ploy<'d is incorrect. Many tables are given, 
but th<'re is less resort to graphical 
ni<-thods of computation than is usual in 
otlKT works on th<' subject. Th<' general 
principk's are next illustrated by worked 
<'X,ampl<'S of actual structures, including 
buiklings, a chinuK'V, water-tower, silos, 
bridge's, and a sole-plate. The book, in 
which th<' att<'mpt has been made to cover 
:i somewh.'it <'xc<'ssive <\\tent of ground, 
ronchKles with a us<>ful vocTibulary of 
lr(-hnical terms in five Ianguag<'S. 



42 



6 



E 






iVZilV^ BOOKS. 



The Handling of the Materials in Concrete 
and Reinforced Conc-ete Construction. 
{'D.e Verarbeitung der 'Baustoffe im 'ftp/on- 
ur.d Lisenbetonhau.) By Herr Riepert. 

Priced. 35 I'f. 

Concrete Pipes. (Cementrohre). By Hcrr 
Riepert. 

Price. 35 Pf. 

The Use of Cement Lime or Trass Mortars 
in the Construction of Dams. (Veber die 
Verwendung ton Ctmentkalk'Oder Trass- 
moriel hei Talsperrenbauten.) 

Price, 30 I't. 

The Use of Concrete and Reinforced Con- 
crete In Kiver Engineering and Drainage 
WorR. {Die VerWenuung vo > "Beton • und 
Eisenbeton tm MelioratiOnsbauWesen.) By 
Fritz Wichmann. 

Price. 1 Mark. 

All publisheil by Cciiientvcrlag, Charlottenburg. 



These four pamphlets are examples of a 
type of monograph which is very familiar 
in Germany. Each deals, in considerable 
detail, with a single question in technical 
practice, and their low price and handy 
form make them very convenient for con- 
sultation in the course of actual practical 
work. The first, second, and fourth are 
issued in a series prepared by the Central 
Bureau for the Advancement of the 
German Portland Cement Industry; whilst 
the third, of a more controversial 
character, is issued by the Association of 
German Portland Cement Manufacturers. 

The first pamphlet named above treats 
of such subjects as centering and shutter- 
ing, the raising of materials, concrete 
mixers, and mechanical devices for bend- 
ing reinforcing rods and tying wires. It is 
abundantly illustrated, and the information 
is concisely expressed. 

The monograph on concrete pipes gives 
a full account of the processes for the 
manufacture of these articles, varying in 
size from the 2-in. pipes used in draining 
agricultural land to large sewers. Re- 
inforced concrete water-pipes and sewers 
are not included. In the smaller sizes, 
concrete pipes are intended to replace clav 
products (earthenware and stoneware), 
whilst in the larger sizes they take the 
place of brickwork. 

The third publication on our list deals 
with a controversy of which little is heard 
in this country, but which has attracted 
much attention elsewhere — namelv, the 
relative merits of mixtures of Portland 



c<ni< nl wilh liin<', .ind of hydraulic lime 
with poz/olanic maU-rial (trass) as com- 
pon<'nts of mortar for masonry dams. The 
pres<nt contribution is written from the 
point of vi<'W of th<' Portland cement 
inanufactur<'rs, and Iarg<'ly takes the form 
of a r<'|)ly to a rec<;'nt manifesto issued bv 
those interested in the sale of trass. A 
good deal of evidence is procluc<'d to show 
that considerable additions of either fat 
lime or hydraulic lime may be made to 
cement-sand mortars without injury to its 
employment in hydraulic engin<'(ring, and 
that such mixtures are often sufx^rior to 
those containing trass. 

The last pamj)hlet d<'als with such 
subjects as canalisation and straightening 
of river channels, the construction of 
enibankments and culverts, and irrigation 
work. Each section receives only very 
brief treatment, but there are many illus- 
trative diagrams, and the little work 
should be found very suggestive by those 
who are concerned with the application of 
concrete and reinforced concrete to these 
purposes, for which the materials in ques- 
tion offer manifest advantages. 



The ChadwicK Public Lectures on Housing. 
1913. By W. E. Riley. F.R.I.B.A., 
M.Inst.C.E., Sup. Architect of Metropolitan 
Buildings and Architect to the London 
County Council. 

Published by the "Builder," Ltd., 4 Catherine Street, 
W.C. Price 6d. 



These interesting lectures delivered by 
Mr. Riley last year have now been 
published in pamphlet form and are well 
worthy of the attention of all those who 
at present are specially studying this vast 
problem of housing. The lectures were 
broadly dealt with under the three head- 
ings : Unhealthy Areas, Unhealthy Houses 
and Cottage Estates. Whilst under the 
two former headings the author deals 
with the housing of the working classes 
in the confines of the London area, the 
last lecture is mainly devoted to the pur- 
chasing of estates by rural and other 
Councils on the outskirts of London and 
yet within easy reach of the Metropolis, 
with a view to erecting healthy dwellings. 

It is impossible here to deal very fully 
with these lectures, and we can only refer 
our readers to the pamphlet, which, we 
would add, has been well illustrated. 



427 




/^^XI^TYI?TT7 x^constructionaj:^ 




POILITE 



ii 



yy 



ASBESTOS CEMENT 

ROOFING TILES 

AND 

WALL & CEILING SHEETS 

FIRE AND WEATHER RESISTING 




^<a>>.<Mi^/<^lfr / 



Should be employed in place of plaster or matchboarding 
as a means of effectually preventing the spread of fire and 
counteracting the effects of Heat, Vibration and Damp. 



Sole Makers 



BELL S UNITED ASBESTOS CO., LTD 

SOUTHWARK STREET, LONDON, S.E. 

"POILITE" WORKS, HAREFIELD. MIDDLESEX 



428 



Please mention this lourndl 'U)hen fiiriling. 






MEMORANDA 




MEMORANDA. 






J 



Memoranda and NeHiis Items are presented under this heading, •with occasional editorial 
comment. Authentic netvs 'will be "welcome. — ED. 



The Concrete Institute Annual Dinner. — TIk- P'ourih Amni.i] I)inn<T of the 
ConcrcU^ lnsliUil<' was hold on May 28th, at the Connaui^lii Rooms, tho new l'rt'sjd<'nt, 
Professor Henry Adams, M.Inst.CE., beinj^ in the chair. Amon^ the visitors ])r<s<'nt 
were Sir John A, Cockburn, K.C.M.G., and Mr. I^Ui-- Marsland ({"'resident of the 
District Surveyors' Association). 

Of the five Vice-Presidents, Mr. II. I). Searles-Wood, F.R.I.B.A., attended, and 
the members of the Council j)resent comjjrised Sir Henrv Tanmr, C'.B., Mr. Bamber, 
F.C.S., Mr. Butler, A. M.Inst.CE., Mr. E. Fiander Etchells, F.Phvs.Soc, Mr. 
J. Ernest Franck, A.R.I.B.A., Mr. Osborn C. Hills, F.R.I.B.A., Mr. \V.' (i. Perkins, 
Mr. A. Alban H. Scott, M.S. A., Mr. E. P. Wells, J. P., Mr. G. C. Workman, M.S.E., 
and Mr. M. E. Yeatman, M.A. 

The followini^ is a summary of the proceedin<^s, in which we have curtailed certain 
portions of the President's remarks which appear to have j:fiven umbrage to a number 
of the members and visitors present and did not seem to be quite in place at a gathering 
of this description, or to accord with the spirit of compromise that ^appeared to have 
some chance of inauguration at the General Meeting that preceded the Dinner. 

77ie President, in proposing the health of The King, described His Majesty as " a concrete 
example of everjthing that was noble." The Queen, Queen Alexandra, the Prince of Wales 
and the other members of the Royal Family he looked upon as " a reinforcement of the 
highest value to the nation." 

Mr. Ellis Marsland (I'resident of the District Surveyors' Association) proposed the toast 
of the evening, "The Concrete Institute." He had watched the progress of the Institute from 
its inception to the present time with \tx\ much interest, and his keynote that night was one 
of congratulation, first of all on account of its membership, secondly on account of its 
objects, and thirdly on account of its work. In the early days of reinforced concrete fon 
struction, one was left to the tender mercies of various patentees and rival firms who magnified 
their own systems to their rivals' disadvantage, but the Institute had changed all that. It had 
evolved order out of chaos, and had standardised and regulated the whole system of con- 
struction so as to make it practicable and workable. He did not mean to imply that there 
were more failures in the reinforced concrete form of construction than in any other — in fact, 
his own opinion was that there were fewer, but still at the same time the public wanted re- 
assuring on that point, and it was the dut\- of the Institute to go into the question, ascertain 
the cause of these failures, and bring about a remedy. He expressed the hope, in the words 
of the Prayer Book, that " unity, peace and concord might prevail " so that the Institute 
might have an uninterrupted and successful career of usefulness and prosperity. (Cheers.) 

The President, in reply, said that for an Institute founded only so recently it had 
achieved a notable result in obtaining over 1,000 members. That was a very good evidence 
that it fulfilled a want, and had a distinct mission to perform. It had many interests, and by 
means of its Committees had already done a considerable amount of useful and practical 
work. It came in on a flood tide, and its immediate success was almost phenomenal. The 
meetings were crowded, and the copies of the papers were eagerly sought after. Then, 
unfortunately, there was an ebb; the attendance fell off because it was found that in concrete 
alone there was not sufficient scope. (Question.) The Council, in considering the matter, came 
to the conclusion that some development was wanted, and he thought they decided to admit 
papers on a constructional steel work where no concrete was employed or only employed in a 



429 



MEMORANDA. [CONCCETE] 



secondary manner. The result was that the interest in the meetings revived and the attendance 
went up again with a bound. Naturally, the Couucil then fully considered the whole position, 
and they came to the conclusion that some amplihcation of the title was desirable. They 
added the sub-title, ""An Institute for Structural Engineers, Architects, etc." Although this 
alteration was welcomed by many it did not give universal satisfaction. Cement makers, 
chemists and contractors felt that they were being left out in the cold. One of the great 
advantages they had enjoyed hitherto had been the meeting together on mutual terms of 
engineers, architects, cement chemists and contractors, and in order that they might make 
solid progress it was necessary that all these varied interests should combine together into one 
harmonious whole. (Cheers.) 

Structural engineering was the one term that best expressed the variety of work of which 
the Institute took cognisance, but that did not mean constructional steel work alone, as some 
seemed to think : it included all varieties of building in all materials where stability was the 
chief aim. It appeared to him that there was scope at the present time in all large buildings 
for the collaboration of the architect and the structural engineer. As to the burning question 
of the position of the so-called specialist, specialist firms were simply contractors, but their 
experts were structural engineers of the highest class, and weie the mainstay of the Concrete 
Institute. (Cheers.) 

The Council had elaborated a scheme of examinations which he hoped by the autumn 
would be in full working order. The intention was that the graduates and associate members 
should be able to obtain certificates testifying to their knowledge of the various branches that 
came under the domain of the structural engineer and the architect. At present the examina- 
tions would be entirely voluntary, but there was no doubt that the time might come when the 
question of making them compulsory would be considered. 

The Council would gladly welcome suggestions from any source that would tend to put 
the Concrete Institute on a firmer basis and make it more useful to the members generally. 

Mr. H. D. Searles-Wood, F.R.l.B.A. (Vice-President, C.I.), proposed "The Visitors," 
and thought they might take it that the Royal and learned Societies which these gentlemen 
so well represented showed, by their presence that night, that they were in amity and concord 
with the Concrete Institute, a very Benjamin among the brethren in respect of age but a lusty 
youth which they w^elcomed into their family circle. 

Sir John A. Cockburn, K.C .M.G. (late Premier for South Australia), in acknowledging 
the toast, confessed that in this matter he was a quack. (Laughter.) He began his practice 
of quackery in reinforced concrete in the year 1880, and he was looking forward to the 
Whitsuntide holidays to put in the biggest job in a reinforced concrete roof he had ever 
undertaken — an unsupported span of 20 ft. by 12 ft. with nothing but reinforcement in the 
concrete. (Renewed laughter.) As a quack, he differed from the quacks in most professions in 
having a profound reverence and admiration for the legitimate practitioners, and thereiore 
he was proud to be among the guests, and especially proud because he recognised that this 
was a live Society and not that dull monotony and uniformity of opinion which was death 
to any institution. In other words, they had the essence of reinforced concrete in the Society, 
they had the thrust of divergent opinions and the tie of association binding them all together 
Mr. E. Fiander EtcheUs, F .Phys.Soc, proposed the health of the President in a very 
amusing speech, and the President acknowledged the compliment. 

Professor E. R. Matthews.— We tender our congratulations to Mr. Ernest R. 
Mattlv-ws, A.M.Inst.C.E., who has recently been appointed to the Chadwick Chair of 
Municipal Engineering at the London University. Mr. Matthews, who has been 
Borough Engineer of I^ridJington for nearly sixteen years, is well known to the readers 
of this Journal by the interesting articles he contributes to our pages from time to time. 

Rosyth Naval Base. — \n conn^^-ction with lh<.' work which is being carried out at 
Rosyth a cfjii^ichrablc aniotint of concrete work is being done. The floors of two of 
the large graving docks ar<' of concr<'t<' som<; 20 ft. thick, this extreme thi(kn<'ss being 
due to the fact that the rock upon which they are built is none too strong. 

About the hardest task with which the contractors have been faced, says the Naval 
and Military Record, is the <-recli()n of th<' huge s<s'i-wall which is being built roimd 
the tidal basin, the diniculti<-s Ix-ing due chiefly to lh<' <'n()rmous size of thi' materials 
which are being used. Work is proceeding on the monolith system, huge concrete mono- 
liths, 40 ft. square, being sunk to the p<'rmanent fotindations, a work which is aaturallv 
laborious ancl slow. However, \h<t most diflictilt part of the er<'Ction of tlie seawall 
has he^-n carri<-d out, anrl rapid pi'ogress is Ix'ing made with the r<>miainder. A large 

430 



Aa;i^AS!]g:'^ i^'emoranda 



numbvi i)l i()iuM<i<* inix<M"< .•ir<' in um, .iikI soiiK-lhiiii^ lik<- i(),()()(i ( u. y<l. of r<-inf()r(<(l 

Hospital Architecture and Construction. In .in arliilc un " Saiiiitoria Hiiildinj^s," 
by Mi. A. Alhaii SroU, ivirnily publisluil in the Hospital, Mr, Scott j4ivos sonio 
particulars of i)laiis conipl<'t<'d by him of a sanatorium for loo b<xls. In dealing with 
iho consiructional dvlails th<' author shows to what an <'Xt<iU concrole could U' us<'d 
with a<l\anta}4<' f'*'' buildins^s of this kind. Wc j^ivi- llu- followinj^ <'Xtract from tho 
arlicU' : -" i n<' construction is as fallows: — 

Floors. — Tho ground to be <'xcavated to the n^'cessary dej)ths and mad<' up to the 
required levels. Not less than in. Portland cement concret<* to b<' plac<'<.l under all 
buiklinijs. These to be prepared for and f)aved with jointless i)aving, as used in many 
institutions, formed of asbestos, etc., fniisiu'd in either J^rey, buff, j^reen, or red colour. 
Walls. — The walls to be rouj^h-cast or other cement coat finish on the outside, and 
would be constructed of p.anels built Ix'tween the reinforced concr<'te structural work in 
the form of columns and beams, each panel beinj^ formed of 3-in. brickwork on the 
outside with a ciivity of 2 in., and a panel on the inside filled in with concrete walls 
2 in. thick, the inside wallin<4 plastered with two coats, the latter bein.^ finished smooth 
ready to receive decoration either in the form of distemper or, wdien the plasterin<^ is 
quite dry, paint and enamel. 

Roofs. — These to be formed of reinforced concrete with special asphalte covering 
on the outside, the inside to be plastered as described for the walling. 

Reinforced Concrete Footbridge at Hltchin. — The footbridge which spans the 
ri\er Hiz, at Charlton, Hitchin, is to be rebuilt in reinforced concrete with an iron hand 
railing. The cost of maintaining the bridge is shared by the Urban District Council 
of Hitchin and by the Hertfordshire County Council. These two authorities have 
decided to share the cost of erecting the bridge. 

Dundee Craig Pier. — In connection with the extension work which has been 
carried out by the Dundee Harbour Board to the Craig Pier, two concrete walls have 
been constructed, each 8 ft. 7 in. thick and about 10 ft. high. 

Administrative Offices for the Port of Para. — In our issue last month (pp. 332- 
338) we publislied an article on these offices. In the course of the article it was stated 
that the internal and external walls were built of concrete blocks. We should like to 
add that the blocks used for the external and internal walls were " Winget " blocks, 
made on " Winget " machines 

Concrete Specifications in Detroit Building Code. — The Detroit City Council 
has recently amended that part of its building code relating to concrete building and 
block construction. Some of the provisions are given below. 

For columns reinforced with longitudinal bars tied at intervals not greater than 
twelve times the least diameter of the bars the safe load shall be computed as follows : — 
Safe load (in pounds) = 550 (A^+124s), where A^ = net cross-section of column in 
square inches, and A, =:= cross-section of longitudinal reinforcement in square inches. 

For columns reinforced with longitudinal steel and with spirally wound hooping 
the safe load shall be computed as follows : — 

Safe load (in pounds) =650 [Ac+12 (A.s+2'4 .4/,)] where .4c = net cross-section of 
concrete enclosed in hooping, .4s = net cross-section of longitudinal reinforcement (not 
to exceed 8 per cent, of A^) and 4,, =^3'i4 d a/p, where d and ^ = respectively diameter 
and pitch of hoop in inches and a = cross-sectional area in square inches of wire or rod 
forming hoop, provided that .1;, shall not be less than 0*5 per cent, nor more than i'5 
per cent, of A ^., and that p shall not be more than one-tenth the diameter of hoop nor 
more than 3 in. 

Flat Slab Floors. — Girderless flat-slab floors reinforced in either two or four 
directions and supported by enlarged column capitals may be constructed according to 
the following principles : — It is assumed that 7t' = total dead and live load per square 
foot; /, length of one side of panel if square or larger dimension, measured from centre 
to centre of columns, if rectangular; B, shorter dimension of rectangular pane) 
measured from centre to centre of columns; L, side of square having same diagonal as 
B I (m a square panel it equals T) D, diameter of column capital at a point where it is 
at least i^ in. thick, and K, bending-moment co-efficient having the values hereinafter 
defined. Then D must not be less than 0*225 L and the sides of the column capital 
must not slope at an angle with the perpendicular of more than 45 (leg., provided that 
P 2 ^431 



„ CQNCDErrE? 



W- 



CON5TRUC TIONAl^ 




NOT A TRICKLE 

OF WATER CAME THROUGH THIS DAM 

IT WAS COMPOSED OF 

UNIVERSAL JOIST 
STEEL SHEET PILING 



^M^pK'^Wf 




Illustration shows dam at entrance to Western Dry Dock, Royal 
Albert Docks. The Piles were our 1^X5 in. Section in 46 ft. 
Lengths, and had to withstand a head of water of 35 ft. 



Contractors : Messrs. G. Shellabear & Son, of Plymouth 

Yr)u can have similar Filing on Hire for your job at the 
approximate cost of ijio per super ft. 



FOR LIGHT WORK USE OUR SIMPLEX PILING 

THE BRITISH STEEL PILING CO. 

4 DOCK HOUSE, BILLITER STREET, LONDON, EX. 



Telegrams: PILINGDOM, LONDON. 



Telephone : AVENUE (5463. 



432 



Please men Iron this Journal •when 'u>riting. 



d 



gKaa'ilf?iri M imOHA NDA 



EfSGlNhl t^lNt. --■ 



il ihc ^l.il) is iiuiciscd in iliickncss .iround ihc r;i|)il;il, the di.iniclcr ol ili,' cipii;!! m;i\ 
bt' rcdui'fd 1>\ one .iiid oiic-h.dl liiiu s iIk lliicUnt'ss of such di(i|). Also / must noi h;; 
iuoi<' th.iii rj5 /)'. 

I'ov sl.ihs rciiilorccd in four directions, iIk' sI(<'1 in llic ccnln' of llir jiands sli.dl Ix- 
(Ksit;n((l lo nsisl a luiulin:^ nioni.-nl of ;i' / ' 25 for inlciior and lu i'22 for i-xlcrior 
panels. Tht^ sU>cl so dcltiinincd shall ho divid<'d equally ainon^ two diaj^onal and two 
cross hanils for square j)ancls. and in the case of icclani^ular j)an<'ls on<-half of this 
steel shall 1 c equally divid<'d helwi-en the diaifonal hands and the nniaind^r hetweon 
the cross hands in propoilion to the ciihes of tluir lenj^ths. 

The neLjative heiuiini* nioni<nl in 180 de^. around the column capital, that is the 
lU'i^ative moment resisted hy two diai^onal and two cross bands at the suj)j)orls, shall !)<• 
taken as ;e/'' 15. 

To compute the concri'U' stress at the column capital a negative bonding' moment 
of :e/.' J5 shall be assumed to be resisted by a band of concrete not wider than D plus 
six times the slab thickness, nor wider than ih<' sunken panel or drop if such is used, 
nor wider than o'4/. 

RcitiforcCii in l^vo Dircclions Only. For slabs reinforcx'd in two directions onlv 
the bending moments in each direction shall be calculated by dividing the slab into 
eight equal strips starting from the centre line of two columns. Each strip shall bo 
regarded as a continuous beam having a positive bending moment at the centre and a 
negative bonding moment at the line of supports. The bending moment at each of 
these points shall be xe/ '* /87v for square panels and wh BI^K in the direction of / and 
7vB^ I SK in the direction of B for rectangular panels. K shall be for interior panels 
as follows, starting at the contr<' line of columns : — 

At line of 

supports. At centre. 
First strip ... ... ... ... ... — 13 + 2b 

Second strip ... ... ... ... ... — 19 +38 

Third and fourth strips each ... ... ... — 58 +5<^ 

For exterior panels these values are to be decreased 20 per cent. Compressive 
stresses in concrete are to be calculated by assuming that the entire width of each strip 
resists the bending moment assigned to it. 

If desired, that portion of the slab lying between column capitals may be regarded 
as a continuous girder and the central portion of the y)late as a slab reinforced in two 
ways and .supported on all four sides. 

That portion considered as a girder shall not be wider than the column capital plus 
six times the thickness of the slab nor wider than 0*5 I. 

The negative bending moment at the support and the positive bending moment at 
the centre shall each be taken as wls-jz^ where .*r is clear span in direction of girder 
and / is distance between column centres at right angles to girder. 

The remainder of the slab shall be known as the inclosed parel and shall bo 
bounded by lines parallel to lines of centre of columns and at a distance from edge ot 
column capitals not greater than two and one-half times the thickness of the slab. 

The bending moment at each edge of the inclosed panel shall be taken as iv p3 h^ 
and at the centre as iv p3 ,'36 in each direction where p is the side of the square for 
square panels and is the side of an equivalent square for rectangular panels. 

No flat slab shall have a thickness at the centre of less than Z/32 for floors, nor 
less than Z/35 for roofs. 

When the slab near the column capital is increased in thickness so as to form a 
sunken (or raised) panel or drop the dimensions of this drop shall be not less than 
o'373 times the panel length in the same direction. 

Ten Concrete Road Essentials.— Mr. Ernest McCullough, Consulting Engineer, 
of Chicago, in a Paper presented at a recent meeting of the Illinois Society of Engi- 
neers and Survevors, gave the following ten essentials for concrete road construction, 
viz. : (i) Intelligent supervision; (2) Careful selection of materials; (3) Proper propor- 
tioning; (4) Proper mixing, using batch mixers only; (5) Moderate use of water; 
(6) Avoidance of a mix leaner than 1:2:3; (7) Use of reinforcing on wide roads and 
over filled spots; (8) Use of combination metal and fibre expansion joint fillers at Inter- 
vals of about 25 ft. across the road; (9) Avoidance of longitudinal joints; and (10) a 
visit to some concrete road under construction before attempting to construct one. 

43.^ 



MEMORANDA. 



ICQNCKETEi 



The Late Mr. W. G. Kirkaldy, A.M.Inst.C.E.— We have to record with deep 
re^>ret the death of Mr. Kirkaldy, who rendered so much service in the investigation of 
concrete and reinforced concrete by his testing work. He was also a member of the 
Sub-Committee of the International Association for the Testing of Materials, in charge 
of investigations into concrete and reinforced concrete, and he was the Chairman of 
the Tests^Standing Committee of the Concrete Institute. We regret that owing to an 
oversight this note did not appear in our May number. 

TRADE NOTICES. 

Appleby and Co. — Messrs. Appleby and Co. advise us that they have recently 
moved to larger premises, and that their new address is 12, The Broadway, West- 
minster, S.W. They have also issued a small leaflet with illustrations of the various 
engineering plant put on the market by them, and we would here draw special atten- 
tion to their pile drivers and concrete mixers. Detailed pamphlets will be sent to those 
interested on application to Messrs. Appleby at the above-mentioned address. 

" Poilite " Asbestos Cement Building Sheets.— These sheets are made for inside 
and outside use. It is claimed for them that they are fire-resisting, sound proof, and 
non-absorbent. Regarding the first named quality, it was reported recently in the 
Architect that the sheets rendered some service at a fire which broke out at a confec- 
tionerv works at Blyth. The works consisted of two buildings, an old and a new 
portion. The old portion was completely gutted, but in the new building all the ceilings 
had been formed by nailing " Poilite " sheets, 5-32 in. thick, direct to the wood joists, 
and by the presence of these sheets, it is stated in the Architect, it was possible to limit 
the area of the fire in the new building to the ground floor. 

" Poilite " can be used for lining walls, partitions, ceilings, etc. It is claimed 
that they do not warp and will lie quite flat. They can be veneered, varnished, or 
primed and painted after fixing. No special tools are required for cutting them, 
and thev can be fixed with nails or brads. The sheets are equally useful in hospital 
or school, hall or bungalow. They are made in various sizes, from 4 ft. by 4 ft. by 
5-32 in., to 12 ft. bv 4 ft. by ts in. Full particulars will be furnished on enquiry to 
\lessrs. Bell's United Asbes'tos Co., Ltd., Southwark Street, S.E., who are the sole 
manufacturers of " Poilite" sheets. 




EVERY INCH 
A MIXER 



THE 

VI CTORIA 

CONCRETE MIXER 

[That's the way 
^^^jto discharge 
concrete 



Write for Catalogue 
No. 29 and learn how 
the mixing is done. 

T. L SMITH Co 

13 VICTORIA STREET, S.W. 



434 



Please menlion this Journal ivhen ivriling. 



/ 




CONCRETE COTTAGE COMPETITION 



, CONJTTJUtTiONALl 



£125 CONCRFTE COTTAGE 



CONCRETE COTTAGE COMPETITIU.W 



WEST 

ELEVATIONS 



'^! 


'^ 


[[^('K.'ra' iS ' 


' ■r'^J 




•■ 1 --■- 
■I ■' : 


- — 






NORTH . 




fj' 








SL-J. 


_i_^ 


i-."| :.„,. 


T J^ 




































50UTH. 






Cofyrisht of Comrttc PuhUcatious. Limited.] 



First Prize Design 



5'TE PLAN 

No. 206 BV Erk.st S. Thompso». Archf.ect. 



CONCRETE COTTAGE CC COTTAGE COMPETITION. 







lM^}mhiM^f--^^ ^ ^^- j- - ^ 



III TRAN5VE „- ^wmmm^ 

KTERNAL . 










Coi>yright of Concrete Piihlica 



CONCRETE 

AND 

CONSTRUCTIONAL ENGmEERlNG 



Volume l.\. No. /. London, J li-V, 1914. 

EDITORIAL NOTES. 



OUR CONCRETE COTTAGE COMPETITION. 

It is with much pleasure tliat we are able lo aniKHince the result of the Concrete 
Cottage Competition organised by this Journal, and the following are the suc- 
cessful competitors : — 

First Prize : One Hundred Guineas. 
Ekxest S. Thompson', Architect, 5, X'ictoria Street, Westminster, London, S.W. 

Second Prize : Fifty Guineas. 

Chas. Bulman Pearson, Licentiate R.LB.A., 109, High Road, Chiswick, 
London, W. 

Third Prize: Twenty-Five Guineas. 

Harold G. Holt, A. R.LB.A., 11, Probyn Road, Wallasey, Cheshire. 

Fourtli and Fiftti Prizes: Ten Guineas each. 

Leonard G. Hannafokd, 42, Rock Park, Rock Ferry, Cheshire. 
^L Crosnier, 20, Brechin Place, South Kensington, London, S.W. 

At the same time, having regard to the large number of competition draw- 
ings sent in, the journal also has pleasure in announcing that, apart from 
the awards under the competition conditions, two consolation prizes of Five 
Guineas each have been awarded lo : — 

J. Cocker and T. Hill, A. A. R.LB.A., 20, Station Buildings, Stamford New 
Road, Altrincham. 

E. W. Stlbbs, a. R.LB.A., Grayshott, ^Larlborough Road, South Croydon. 

The whole of the drawings that have been sent in for this competition wilt 
be exhibited in the Lecture Hall of the Surveyors' Institution, 12, Great George 
Street, Westminster, S.\\\, from July 6th to July nth inclusive (ii a.m. to 
6 p.m. daily). 

We present on the following pages, firstly, the assessors' report; secondly^ 
a commentary on the competition ; thirdly, the illustrations of the five designs, 
to which the assessors have accorded the five prizes ; and, fourthly, the specifica- 
tions that have accompanied the designs. 



CONCRETE COTTAGE COMPETITION. (CDNCBETE3 

THE ASSESSORS' REPORT. 

The assessors express their satisfaction with the number and general character 
of the designs, which show the interest taken in the simple, but important, 
economic problem of cheap cottage building. 

The special character of the competition is its demand for a design suitable 
for execution mainly in some form of concrete, instead of wholly in the usual 
materials of brick, tile, slate, stone, or carpentry. 

This requirement necessarily affects the planning by imposing great sim- 
plicity of external form. It also tends to exclude or render superfluous the 
picturesque breaking up of the elevations. 

The architectural problem is, therefore, not so easy as it is simple, pre- 
cedents not lying at hand in the countryside or in local county traditions. 

The conditions of concrete construction and design being granted, the 
main problem is the provision of the best accommodation possible for the fixed 
limit of expense. 

The conditions explain that the sum of ;^i25 is exclusive of builder's 
profit, sanitary fittings (which would be of stock prices), fences, land drainage, 
etc. The cost of the drains was expressly excluded, so that comparison could 
not hastily be made with the cost of completed cottages, which may or may not 
have been connected with sewers or have involved expensive drainage. The 
sum of £j2^ was settled for the purposes of the competition, and must not be 
taken as the total cost of completing any of the cottages. 

The arrangement of the plan within these limits is the remaining but pre- 
eminent condition — domestic economy and the requirements of three bedrooms 
for the family with the living room and necessary adjuncts ruling the decision, 
and leaving no space to be wasted. 

The Assessors award the first prize to Design No. 206, the second prize 
to Design No. 75, the third prize to Design No. 193, the fourth prize to Design 
No. 205, and the fifth prize to Design No. 56. 

(Signed) Max Clarke, 

Beresford Pite, 
Edwin O. Sachs. 



436 



fA:^^'^lJS^ CONCRETH COTTAGE COMPETITION. 

COMMENTARY ON THE £125 CONCRETE COTTAGE 

COMPETITION. 



Tin: Rsiilt of this (M)ni)"H'tili()n is clrciclcclly iiitcrcsling, botli from an archi- 
tectural point of view and as helj^ing' to solve the economic problem as 
to the b<\st means of housing the rural population who are in receipt of a 
very small wcekK wage, and c()ns<*(|uently unable to pay even a reason- 
able amount of rent for a cottage. Much time and thought lias been 
exjx-nded in attempts to decide how much accommodation shall be pro- 
vided in ordi'r to decently house a growing and increasing family, so that 
there may not be overcrowding. 

Naturally some happy medium must be arrived at which seems to 
have been met by the conditions of this competition. It provides for a 
living room or kitchen and sleeping accommodation for father, mother 
and four children, which may be interpreted as a kitchen, three bedrooms 
and a scullery or wash-house, with places for food, fuel and sanitary 
accommodation. In country districts the provision of sink, w.c, and 
the drainage thereto, if water-borne sewage is contemplated, usually 
involves an outlay out of all proportion to the cost of the main building, 
and the question as to whether a detached earth closet would not meet all 
the requirements of health and sanitation is one which merits the careful 
consideration of those who are interested in the housing problem, so that 
some broad principle should be agreed upon. This point has not 
received the consideration it deserves. 

Another matter which is of great importance in the housing problem 
is the area and the height of the rooms. It is one thing for rooms in 
town dwellings to be at least 8 ft. 6 ins. high, but it is quite another 
matter in the country where all the doors and windows can be left open, 
and where probably the occupants spend the greater portion of their life out 
of doors. In the latter case it might reasonably be presumed that a less 
height than 8 ft. 6 ins. would be sutficient, without any detriment to the 
health of the occupants. 

All these questions are of vital importance in the production of an 
economical design. The grouping of a number of cottages no doubt 
tends to economy, but in cases such as the present problem, cost is the first 
consideration, and groups, instead of isolated buildings, would appear to 
be one step which should be agreed upon as giving the best return for a 
fixed outlay. 

The public generally, and some designers, do not seem to differentiate 
between a cottage for the labouring classes and a " week-end " cottage. 
Money is wasted on the little extravagancies of the latter which are quite 
out of place in the former, as the less weekly rent a cottage can be let for, 
the g:reater the advantage conferred upon the occupier. Questions such 
as these led the proprietors of " Concrete and Constructional Engineer- 
ing^ " to promote this competition and to offer five prizes the aggregate 
value of which amounts to the very handsome sum of ;^204 15s., the first 
prize being one hundred guineas, the second fifty guineas, the third 
twenty-five guineas, and two prizes of ten guineas each. 

«^ +37 



CONCRETE COTTAGE COMPETITION. [CQNCBETE] 



A large number of drawings, 249 sets in all, were sent in, amongst 
which nearly every type of cottage was represented in some form or 
another. 

In most parts of the country the materials for the aggregate of 
concrete can be obtained in some form, and if the material is dealt with 
in a proper manner the construction can be made efficient and lasting with 
a minimum of cost for upkeep, an important item from the owmer's point 
of view. 

The assessors therefore decided that those designs in which concrete 
was largely used complied to the greatest extent with the requirements 
of the conditions, and as a result selected design No. 206 as the most suit- 
able to which to award the first prize of one hundred guineas. It is an 
isolated one-storey cottage, in which concrete is used throughout, having 
an excellent plan wath a central living room 185 ft. in area, and three 
bedrooms, being 102 ft., 106 ft. and 125 ft. in area respectively. There 
is a scullery 56 ft. in area and food store off the scullery, and a w.c. and 
fuel store, both entered from the outside. The rooms are 8 ft. in height, 
and there is no w^aste space whatever in the plan, the whole being con- 
veniently arranged with a view to economy of labour in carrying out the 
domestic duties of the housewife. The windows are so placed that each 
room will get sun during some hours of the day. The flat roof adopted, 
while being somewhat novel in design, would be a pleasing feature in 
the scheme, and is skilfully treated so that only one rainwater pipe is 
required. The author is to be congratulated on his clever treatment of 
the problem, and it is to be hoped the design will be carried out at an 
early date. The total cube is 8,130 ft., and the estimate cost is ^^125 los. 
This sum, according to the conditions, does not include drainage, water 
supply, sanitary equipment or plumbing, and the work to be carried out 
by an owner buying his own materials and employing direct labour. 

The second premium of fifty guineas goes to design No. 75, a one- 
storey pair of cottages. In this concrete is also used throughout for the 
construction. There is a central living room 154 ft. in area and three 
bedrooms, having areas of 126 ft., 68 J ft. and 68 J ft. respectively, the 
scullery is 44 ft. in area, there is a food store entered from the scullery, 
and a w.c. and copper both outside. The rooms are g ft. high to the 
crjllar of the roof, and about 7 ft. 6 in. to the junction of the sloping roof 
with the wall fa(^e. 

The total cube for the two cottages is 14,362 ft., and the estimated cost 
is ^249 6s. fod. at 4,\d. All the windows face east or west, there being 
none at the ends. Any number of cottages could be built in a row at a 
minimum of cost. Hm- roofs are sloping, cover<'d with some form of 
cement tiles, and the small proj<'(iing pon^hes constitute a pleasing break 
in llie long lin<' of tin* frontage to the west. 

Design No. 193 takes the third place, with a premium of 25 guineas, 
a pair of two-storey (V)ttages, (^oncrc^te being the material used. In this 
design there is a central living r'Of)m with a scullery and one bedroom on 
the ground level, arid two bechvioms on the first floor. 

The living room is 151 {{. in area, and tlu' thn'e bedrooms 169 ft., 
T42 ft., and 71 ft. in area respedix-el y ; the s(^ii11ery is 73 ft. in area; a food 

438 



a, CXDN.TrUlKTION A I. 



CONCRliTE COTTAGE COMPETITION. 



store is i'nl<'i('(l fioin llx' s(-iill('i\ , .-iiul :\ \\ x . aiul fuel store both oiitsicK 
the hor.st'. 'V\\v rooms on llu" f^rouiul lloor iwc S tl. i^ in. In^Hi, ,'iiul tli<- 
two hctlroonis on llic lirsl lloor 'avv S It. ^:; in. .'ixcra^a* high, 'i lu- t'Xtrricjr 
is irtati'cl with j)r()ji'(t in^: hands ol concR'tc and a rather <*\p(*nsiv<* cornice 
for this eiass ol" house, whicii inii^ht well he sini|)lilied in execution. The 
l)itch ol tlu' concrete rool is very Hal and shows very shghtly above tlic 
[)arapet ; " Ilvrib " is used in tile reinforcxMiient of the con(Tete, in com- 
iiination with a limited use of l)ars. The ck'sijj^n is suitable for building in 
blocks of four in a row; a black tarred skirting protects th<; lower portion 
of the exti'rnal walls from wet and damp, and would be effective in 
ex<'cution. 

Hie totrd cuIk' of the two is 14,718 ft., and the estimated cost is 
^."245 6s. at 4d. per cu. ft. 

One of the prizes of ten guineas goes to design No. 205, which is 
brackett<'d with Xo. 56. No. 205 is the only one of the premiated designs 
in which an approximately square plan is adopted for a block of two 
cottages, the living room being in front, with the scullery, fuel larder, 
and w.c. at the rear, with three bedrooms on the first floor. The living 
room is 156 ft. in area, the scullery 61 ft. in area, and the three bedrooms 
135 ft., 80 ft., and 50 ft. in area respectively. The kitchen and scullery 
are 8 ft. 3 in. in height, and the bedrooms on the first floor are 8 ft. in 
height. A good feature in the bedrooms is that the windows are high up 
and close to the ceiling, so leaving no space for stagnant air above the 
window heads. The design is simple, depending on raised bands and 
panels for effect, which give the exterior a somewhat monumental 
character. The roof is of concrete hipped all round, and there is a sus- 
pended ceiling which may be considered one of the items of luxury in the 
design ; the fireplaces are cleverly arranged in the centre of the block, and 
the flues carried up in one stack for the pair of cottages. 

The design is suitable for erecting in pairs, not in rows. The total 
cube for a pair is 14,555 ft., and the estimated cost ;^242 12s. for the two 
at 4d. percu. ft. Design Xo. 56 is bracketted with Xo. 205, both receiving 
prizes of ten guineas. 

This scheme shows a block of two cottages with two bedrooms to each 
cottage on the first floor, which is entirely in a mansard roof, constructed 
of concrete. The balconies to the first-floor windows might well be 
omitted as being both unnecessarv and unsuitable in houses of this class. 
If a part of the money saved on the omission of these was to be spent on 
a raised block to support the water butts it would be appreciated by the 
occupier. A water butt is a convenience, and much more so when it is 
placed so that a bucket can be put under the wooden tap in general use. 
The same remark applies to Nos. 193 and 205. 

All these competing gentlemen should recollect in future that water 
butts are for use more than for ornament and cease to be a pleasing feature 
in the design when they become old, in want of paint, and probably with 
a fungoid growth as an architectural dressing. 



4>9 



CONCRETE COTTAGE COMPETITION. 



[CaNCBETEJ 



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CONCRETE COTTAGE COMPETITION. 




CONCRETE COTTAGE COMPETITION. 



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CONCRETE COTTAGE COMPETITION. [CQNCBETE] 



SPECIFICATIONS TO COMPETITION DESIGNS. 

With Design No 206 [B} Ernest S. Thompson, Architect). 

In accordance with the pubHshed conditions, I have pleasure in submitting herewith a 
sheet of drawings illustrating a cottage which provides all the accommodation asked 
for, is economically planned, sound, cheap and substantial ; is one storey high, with a 
minimum use of timber, has good square rooms, and no dark corners. Each cottage is 
detached, and is placed on the site so that every living room gets the full benefit of a 
southerly aspect. The bedrooms also are lighted with due consideration. 

The external walls are of 4^ in. solid concrete blocks and breeze concrete partition 
slabs 2}j in. thick, with a 2-in. cavity in between, w^ell tied together. These slabs would 
also be used for the partition walls. 

The external treatment is extremely simple, depending more for effect upon pro- 
portion and shadow, than the use of architectural adornment. 

The floors of bedrooms are covered with i-in. grooved and tongued boarding, 
nailed direct to the breeze concrete. 

The other floors would be finished in granolithic, or concrete tiles. 

All internal surfaces of walls would be skimmed one coat, the boarded ceiling 
stained and varnished. 

The drawings will be found quite explanatory of all other necessary points. 

Specification. 

Excavator. — Excavate site to a depth of 12 in. 

Excavate for drains. 

Provide and lay concrete beds under footings of external walls 2 ft. by 6 in. thick, 
composed of i part Portland cement to 6 parts of approved pit gravel, not exceeding 
i^ in. gauge, with sulificient sand to fill the interstices. 

Concretor. — Provide and lay concrete bed 4 in. thick, composed as before, under the 
surface of all floors. 

The floors to the three bedrooms to be finished with 2 in. of fine coke breeze 
cement ; the remaining floors with floated granolithic surfaces. All steps to be in 
concrete ; ditto hearths. 

Lintels to windows and doors to be in concrete, reinforced with steel joists, or bars, 
as may be deemed necessary. 

The quoins to all external angles of walls to have rock-faced surfaces, the re- 
maining blocks of walling to be plain-faced. 

The plinth to be finished with chamfered course, as shown on detail. 

The remaining walls internally, such as fireplace openings, etc., to be formed 
with concrete bricks ; the fireplaces to have fireclay brick linings. 

Chimney cap to be plain, splayed and throated, and the crow-steps to chimney on 
west elevation to be plain 3-in. slabs, weathered and throated. 

'I"he concrete flat to roof to be formed of an average thickness of 3^ in., with a 
surr(;unding kerb and one outlet to rain-water pipe. 

" St-lf-centering " has been ado[)ted, with a view to economy and efiiciency, and 
to obviate the use of temjjorary wooden shuttering. 

Provi<l<- and coat th<- <-\Urn:i\ surfa(<' Hat roof with thre<' coats of Ironite wati^r- 
proofing comj)ound. 

Carpenter and Joiner.- The limber for all joiner's work to be best quality vellow 
deal, with the exception of I he ceiling boarding, which will be grooved, tongued and 
beaded match-boarding, in narrow widths. 

Door and winclow furniture to be of a substantial character. 

iHasterer.- I'hc whole of the internal surfaces of the walls to have one coat of 
skimming, with th<- <xc<pl ion hi \h<- fu<I sl()r<- and w.c., which would Ix' lim<'-wash<'d. 

Plumlier, Painter and (Hazier. -Plumbing work to be of the best character. All 
glass to windows 21-0/. sheet. 

All external and internal woodwork and ironwork' to be p;iinled three coats b(\st 
oil paint, in addition to stopping and priming. 

4+4 



rTcoN>TPurriaNM^ CONCRETE COTTAGE COMPETITION. 



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List of Fitllngs. etc. 

Kililiiii Kaiij,'i' ... ... •• •■• ••• ••• ])• (• 

I" irrphiccs and M.mlcls ... ... ... ... ... ... ,, , 

Sink ... ... ... ■•■ ••• ••• ••• ••■ ••■ 15 1 

Shelviufj... ... ... ••• ... ... ... •-. .•• ,, , 

Door I'urniturc ... ... ••• ... ... •.• ... i* , 

Windows, do. ... ... ... ... ... ••• ... •■• ,, , 

Statement of Cost. 

I'o airivo ;il ;i l;iii l\ ;i|)|)i()xiniat(' cslinialc of (lie cost, 1 lia\<" lakcii oul a hill of 
(.|uanliti(s, which I have priced u])on cstahHshcd lif^urcs, with a due rcj^ard to the 
coiuhlioiis staled, viz., the huildini^s are to he erected hy the cniployer''s own lahour, 
without the introduction of a third i)arty, and that no main (h-ainaj^e, or f^as or water 
suj)ph', or an\ iikinihini^ or sanitary work, or equi])nient other than a lenj^th of 40 ft. of 
4-in. drain is required, and I bv^ to a])])end a summary thus obtained of the cost of 
eacli trade, inclusive of all fittinifs : — 

£ s. d. 
Excavator and Drainer ... ... ... ... ... ... ... ... ...400 

Concretor : £ s. d. 

Walling 35 o o 

Foundations ... ... ... ... ... ... ... ... 15 o o 

Roof ... ... ... ... ... ... ... ... ... 25 o o 

Floors ... ... ... ... ... ... ... ... ... 500 

80 o o 
Joiner : 

Windows 
Doors ... 
Ceiling 
Floors ... 

T,^ 10 o 

Plumber, Painter and Glazier ... ... ■• ... ... ... ... ...800 



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With Design No. 75 {By Chas. Bulman Pearson, Licentiate R.I.B.A.). 

Description and Remarks. — The author has endeavoured to carry out the conditions 
of the Competition. The areas of the rooms have been closely adhered to and the 
accommodation provided is, in his opinion, consistent with cost. 

Concrete to be used wherever possible and the amount of woodwork reduced to ^ 
minimum. This being necessary in the case of doors, cupboards, etc. 

It is proposed that the floors and roof be of concrete, the floor surfaces to be 
finished with a patent composition such as " Doloment " or other approved method. 

The roofs to be covered with approved concrete tiles. If not contrary to the spirit 
of the Competition, it is suggested that a good coloured red tile would form a verv fine 
contrast to the other portions of the buildings. 

The walls and chimney stacks to be in concrete built in situ, the interior partitions 
to be in slab concrete. The external faces of the walls, where show^n on drawings, to 
be finished in plaster or rough-cast trowelled smooth. 

All woodwork has been eliminated from windows, the method proposed being 
shown on the details. 

Specification. 

Materials. — The cement to be best Portland complying with the requirements of 
the specification adopted by the British Engineering Standard Committee. 

The sand to be from a well-known local pit ; it should be clean and free from 
organic or earthy matter and w^ashed if required. The aggregate to consist of a good 
local material consisting of gravel, hard stone, or other suitable material ; this should 
be clean and regular, varying in size, all to pass through a |-in, mesh. 

The proportions of concrete should consist of i part cement, i^ of sand, to 2^ parts 
aggregate. 

The concrete should be mixed in small batches and in accurate proportions, and 
should be laid as rapidly as possible. 

The amount of water to be added depends on the temperature at the time of 
mixing. Clean fresh water only to be used. 

The centering or casing to be so constructed as to remain rigid and unyielding 
during the laying and punning of the concrete, and should be arranged to permit of 
casing and removal without jarring of concrete. 

4+5 



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CONCRETE COTTAGE COMPETITION. 1CDNQ3ETE] 

All other materials to be the best of their respective kinds, free from all defects. 

List of Fittings, etc. 

£ 

Kitchen Range ... ' ... .. ... ... ... ... ... •.• 3 

\\'ashing Copper ... ... ... ... ... ... ... ... i 

Bedroom Fireplaces (3) ... ... ... ... ... ... ... 4 

Dresser ... ... ... ... ... ... ... . • ... ••• 2 

Statement of Cost. 

The cubical contents are 14,194 cu. ft. the pair. 

This is arrived at as follows : — 

Ft. 

Main Block 73 ft. 3 in. x 15 ft. 6 in. x 11 ft. 6 in. = 13,057 

Entrances (2) 5 ft. o in. x 3 ft. 6 in. x 11 ft. o in. = 385 

W.C 7 ft. 6 in. x II ft. o in. X gft. oin.= 776 

Chimney Stacks 3 ft. 6 in. x 2 ft. 6 in. x 5 ft. 6 in. = 144 

14,362 per pait 



Estimated cost per pair— 

= 14,362 cu. ft. at 4 i-6d. =^£,'249 6s. lod. 
= ;^"i24 13s. 5d. per cottage. 
It is considered that the price per cu. ft., 4 i-6d., is sufficient, seeing that there is 
no fencing, paths, water supply, plumbing, or land drainage to be included, and that 
the cottages are to be put up in a series of six. 

With Design No. 193 By Harold Q. Holt, A.R.l.B A). 

The cottages shown on the accompanying drawing have been designed in accordance 
with the conditions, and with a view to strict economy, combined, so far as possible, with 
a reasonably pleasing appearance, suitable for rural districts. The author has made an 
effort to get away from the somewhat box-like appearance which follows a flat roof 
treatment in a small building. 

Standardisation.- — In planning the cottage the view was to repeat the parts as much 
as possible. On consideration the author decided that to merely design a cottage 
suitable for brickwork, timber and slated roof, and label it " concrete block cottage," 
though allowable under the conditions, was not advancing the purpose of the Com- 
petition very far, and made an effort to design a cottage where repetition of parts would 
enable it to be economically built, with outside walls, etc., of concrete moulded hori- 
zontally (see specification). 

The accommodation shown complies with the conditions, and is substantially that 
reported as desirable by the Departmental Committee which investigated the Small 
Holders' housing question. 

Through ventilation is obtained in the best rooms and staircase. Owing to the 
low thermal conductivity of concrete, the cottage would be cool in summer and warm 
in winter. Water-tightness obtained by careful grading, etc., and oil-mixed finish 
suggested if in wet locality. 

Specification. 

Concrete— Cen^cnt for concrete to be ]\)rtland, to British Standard .Specification, 
medium setting. 

Aggregate (according to locality) to be clean, hard, broken ballast or gravel and 
sand, free from loam, etc., carefully graded by experiment, and all to pass ^-in. screen. 
Mixing \() l>c in proportion of 4 to i by measure, mixed on clean wood bankers (or in 
hand-jK)wer mixer if ax-ailable) while dr\' until thoroughly incorj)orated, water to be 
then arlded l)\- spra\, and mixing continued until the concrete is even in consistency and 
in a senii-lUiid state. 

R<infor{<m<nl. In oiitsick- walls and beams .j-in. rods an<l steel wir<'s 12 .S.W.G. 
In floor and roof Hyrib lathing, 28 .SAV'.(i. 

Method of Construction and Waterproofing.- l'^)undation of 6 to 1 concrete to be 
laid in trench with rebate 7 in. wide and 3 in. deej). Horizontal close-boarded wrought 
sheeting as form to he laid with base line near trench on strong planks (sheeting of 
6-in. by l^-'in. boards, to \n: used for flooring at c()nij)letion) soft-soajx'd for concreting. 

Cf)ncr^'te car^-fullv tam|>ed in 2.],-in. lay<r; r<'inf()rc'em<'nt lai<l on 2.]j-in. lay<'r again. 
If in a w<t lf>cality it is suggest<-d llw finisliing \ in. should be oil-mixed concrete (Ik'.'ivv 
p<-trol<'um residuum). TIk- window sashes ;ind dooi" frames to Ix' l)<'d(l<'<l in moulds and 

446 



I 

i 



j,CTON.vrPUCTIONAl,) 



CONCRETE COTTAGE COMPETITION. 



C()iu'i<'l<'il up l(». Surfatx' scixhhUcI off. Concix-to allowed to s<'t for at U-ast four days, 
th<n sli<<tini^ <lia\\ii awav. Allow to season and rais<; in position with blocU, k*^s 
ami taikU' bv roixs t'u'd to planks (whicli pi-ot<cl tlu' surfaco and distributo the wc-i^hts), 
and slipjHd into r<'bat<- in footinj^s. Strutti-d up and ^'rout^-d in. Thn'O tyiK'S of forms, 
as sk<tc-]i. Joint niaik' b\' rod i;rout< d round at junction of < ac h inould<d j)i<'<<-. 

First Hooi- and roof ^.Uin. ll\rib 2S i^au^c lathinj^ concreted in. 

Partition between scullerv and Ix'drooni No. 3, llyrib plaster skininied both sides, 
linishini^' 2 in. 

Roof iinislK'd with :,'-in. oil-niix<'d eoner<'t<', 

I'^liK's and walls n<'Xt stair of brickwork. 

Floors. — KitclK'n .and bedrooms to have centre boarded square, of 6-in. by -j^-in, 
iniporl<'d Baltic whit<", square joint<>d and laid in tar as blocks; ^-in. rem<nt finish 
round, and to all oth<'r rooms. 

Windows.— 2-in. red deal standinj:^ sashes (or fast sheets), no frames. All out of 
4-in. bv 2-in. casem<'nts cut out. Mill made. Glazing, 21-oz. sheet. 

Doors.—- ^-in. T and G boards on ir^-in. battens. Mill made. 

Stairs.- i-in. trend, -^-in. risers on 3-in. concrete carriage, for fire protection. 

Walls lime-whited outside, plaster skimmed one coat inside. 

External wood, prime and paint three coats oils; intirnal, prinK- and paint two 

coats. 

List of Fittings, etc. 

The following net p.c. sums are included in estimate : — 
No. 2 Kitchen Ranges, @ ^^2 los. ... 

Xo. 4 C. I. Mantel Registers to Bedrooms i and 2, @ i6s 

Ironmongery for each Cottage, @ £2 los. ... 

No. 3 R. W. Butts, @ 15s 

No. 2 Kitchen Dressers, 4 ft. 3 in. x 2 ft. q in. x i ft. 4 in., @ £2 . 
No. 2 Kitchen Cupboards, @ ;^i ... 
No. 4 Small Cupboards, @ 7s. 6d. ... 

jC22 ig o 
Estimate of Cost. 

;^25o the pair — arrived at as follows :— 

A. Building cubed outside measure and 19 ft. 3 in. high from bottom of footings. 

14,717 cu. ft. £ s. d. 

At 4d. per ft. cube ... ... ... ... ... ... ... ... 245 6 o 

Contingencies, say ... ... ... ... ... ... ... ... 4 14 o 

^250 o o 



I 


s. 


d . 


5 








3 


4 





5 








2 


5 





4 








2 








I 


10 






B. Rough quantities taken and priced out by author from reliable information. 
Following are the items condensed. Prices for concrete for walls, etc., including 
sheeting and reinforcement, given by a reliable builder at 43s. per cu. yd., checked by 
price obtained from a person who has actually carried out this type of construction three 
vears ago with walls 6 in. thick at 5s. per yd. super. Allowing 20 per cent, advance 
in prices, the author considers it on right side (the building owner being the direct 
employer and the economy in sheeting) in putting this concrete at ^2 2s. per cu. yd. 

Schedule. 



£.2 2s. per yd. cube 



Excavating and Drains 

Wall, Floor and Roof Concrete, @ 

Foundation and Ground P'loor ... 

Brickwork 

Cement Floating, etc. 

Wood Floors ... 

Windows and Glazing 

Door Frames, internal joiner j- .. 

Hyrib, Plastering and Painting 

P.C. sums as per list 



This allows of a sum of ^4 5s. 4d. being placed for contingencies if required, or toward? 
plumbing and fencing. 



£ 


s. 


d. 


3 


10 





... 127 


13 





13 


I 


6 


10 


10 





5 








5 


13 





15 


6 


8 


21 


2 


6 


20 


18 


6 


22 


19 


6 


;^245 


14 


8 



4^7 



CONCRETE COTTAGE COMPETITION. 1CQNQ3ETE3 

With Design ^o. 205 {B